Acknowledgment feedback techniques in shared radio frequency spectrum

ABSTRACT

Methods, systems, and devices for wireless communications are described that provide for group or one-shot acknowledgment (ACK) feedback reporting, in which feedback for a number of different downlink transmissions may be provided by a user equipment (UE) to a base station. A base station may trigger a one-shot feedback report that includes less than all of the ACK feedback that is available at the UE to provide in a report. The ACK feedback may include an indication of an ACK or a negative acknowledgement (NACK) along with information related to a data indicator associated with the downlink transmission. In some cases regular ACK feedback reports and one-shot feedback reports may be multiplexed and transmitted by a UE. Further, a last downlink transmission to be included in a one-shot feedback report may be determined based on a receipt time of scheduling information or an ACK feedback timeline.

CROSS REFERENCE

The present application for patent claims the benefit of IndiaProvisional Patent Application No. 201941019598 by KHOSHNEVISAN et al.,entitled “DETAILS OF ONE-SHOT HARQ-ACK TRANSMISSION IN NRU,” filed May16, 2019, assigned to the assignee hereof, and expressly incorporated byreference herein.

BACKGROUND

The following relates generally to wireless communications, and morespecifically to acknowledgment feedback techniques in shared radiofrequency spectrum.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., time, frequency, and power). Examples of suchmultiple-access systems include fourth generation (4G) systems such asLong Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform spread orthogonal frequency division multiplexing(DFT-S-OFDM). A wireless multiple-access communications system mayinclude a number of base stations or network access nodes, eachsimultaneously supporting communication for multiple communicationdevices, which may be otherwise known as user equipment (UE).

Some wireless communications systems may support acknowledgment (ACK)feedback to indicate if a wireless device (e.g., a UE) successfullydecodes downlink messages (i.e., data transmissions) where the downlinkmessage decoding is based on one or more detected downlink controlmessages (e.g., a downlink grant or downlink control information (DCI)).In deployments supporting shared or unlicensed radio frequency spectrums(e.g., unlicensed NR), one or more downlink messages may not be receivedcorrectly (e.g., due to a hidden interfering node) and the wirelessdevice may not provide ACK feedback based on all of the downlink controlmessages. Further, in some cases a wireless device (e.g., a UE) may notbe able to transmit ACK feedback when the medium is occupied by anothertransmitted (e.g., when a listen-before-talk (LBT) procedure fails).Techniques to enhance system performance in cases where one or moretransmissions may not be sent or received are thus desirable.

SUMMARY

The described techniques relate to improved methods, systems, devices,and apparatuses that support acknowledgment feedback techniques inshared radio frequency spectrum. In various aspects, the describedtechniques provide for group or one-shot acknowledgment (ACK) feedback(e.g., hybrid automatic repeat request (HARQ) feedback) reporting, inwhich feedback for a number of different downlink transmissions may beprovided by a user equipment (UE) to a base station. In some cases, abase station may trigger a one-shot feedback report that includes lessthan all of the ACK feedback that is available at the UE to provide in areport. For example, ACK feedback associated with a particular componentcarrier (CC) of a set of CCs may be requested by the base station andtransmitted by the UE. In some cases, additionally or alternatively, ACKfeedback may include an indication of an ACK, a negative acknowledgement(NACK) may be provided along with information related to a new dataindicator (NDI) associated with the downlink transmission for which thefeedback is provided. In some cases, additionally or alternatively,regular feedback reports and one-shot feedback reports may bemultiplexed by a UE and transmitted to the base station. Further, insome cases, a last downlink transmission to be included in a one-shotfeedback report may be determined based on a receipt time of schedulinginformation or an ACK feedback timeline. It is to be noted that variouselements detailed as follows may be combined between independent claimsdescribed herein.

A method of wireless communications at a UE is described. The method mayinclude determining HARQ feedback for a set of downlink transmissionsfrom a base station, where each downlink transmission of the set ofdownlink transmissions has an associated data indicator that indicateswhether the downlink transmission includes an initial transmission ofdownlink data or a retransmission of previously transmitted downlinkdata, receiving, from the base station, downlink control informationthat indicates the UE is to provide a one-shot feedback report for atleast a subset of the downlink transmissions, identifying, for eachdownlink transmission of at least the subset of downlink transmissions,associated HARQ feedback that includes anacknowledgment/negative-acknowledgment indication and the associateddata indicator, where a default data indicator is identified as theassociated data indicator for one or more downlink transmissions in anabsence of scheduling information for a HARQ process identification ofthe one or more downlink transmissions, and transmitting, to the basestation, the one-shot feedback report including the HARQ feedback for atleast the subset of the downlink transmissions.

An apparatus for wireless communications at a UE is described. Theapparatus may include a processor, memory coupled with the processor,and instructions stored in the memory. The instructions may beexecutable by the processor to cause the apparatus to determine HARQfeedback for a set of downlink transmissions from a base station, whereeach downlink transmission of the set of downlink transmissions has anassociated data indicator that indicates whether the downlinktransmission includes an initial transmission of downlink data or aretransmission of previously transmitted downlink data, receive, fromthe base station, downlink control information that indicates the UE isto provide a one-shot feedback report for at least a subset of thedownlink transmissions, identify, for each downlink transmission of atleast the subset of downlink transmissions, associated HARQ feedbackthat includes an acknowledgment/negative-acknowledgment indication andthe associated data indicator, where a default data indicator isidentified as the associated data indicator for one or more downlinktransmissions in an absence of scheduling information for a HARQ processidentification of the one or more downlink transmissions, and transmit,to the base station, the one-shot feedback report including the HARQfeedback for at least the subset of the downlink transmissions.

Another apparatus for wireless communications at a UE is described. Theapparatus may include means for determining HARQ feedback for a set ofdownlink transmissions from a base station, where each downlinktransmission of the set of downlink transmissions has an associated dataindicator that indicates whether the downlink transmission includes aninitial transmission of downlink data or a retransmission of previouslytransmitted downlink data, receiving, from the base station, downlinkcontrol information that indicates the UE is to provide a one-shotfeedback report for at least a subset of the downlink transmissions,identifying, for each downlink transmission of at least the subset ofdownlink transmissions, associated HARQ feedback that includes anacknowledgment/negative-acknowledgment indication and the associateddata indicator, where a default data indicator is identified as theassociated data indicator for one or more downlink transmissions in anabsence of scheduling information for a HARQ process identification ofthe one or more downlink transmissions, and transmitting, to the basestation, the one-shot feedback report including the HARQ feedback for atleast the subset of the downlink transmissions.

A non-transitory computer-readable medium storing code for wirelesscommunications at a UE is described. The code may include instructionsexecutable by a processor to determine HARQ feedback for a set ofdownlink transmissions from a base station, where each downlinktransmission of the set of downlink transmissions has an associated dataindicator that indicates whether the downlink transmission includes aninitial transmission of downlink data or a retransmission of previouslytransmitted downlink data, receive, from the base station, downlinkcontrol information that indicates the UE is to provide a one-shotfeedback report for at least a subset of the downlink transmissions,identify, for each downlink transmission of at least the subset ofdownlink transmissions, associated HARQ feedback that includes anacknowledgment/negative-acknowledgment indication and the associateddata indicator, where a default data indicator is identified as theassociated data indicator for one or more downlink transmissions in anabsence of scheduling information for a HARQ process identification ofthe one or more downlink transmissions, and transmit, to the basestation, the one-shot feedback report including the HARQ feedback for atleast the subset of the downlink transmissions.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the transmitting may includeoperations, features, means, or instructions for transmitting only theone-shot feedback report with an uplink transmission to the basestation. In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the one-shot feedback reportincludes one or more of acknowledgment (ACK) indications, negativeacknowledgment (NACK) indications, the data indicator, or combinationsthereof, that may be each associated with a corresponding HARQ processidentification (ID) for a downlink transmission of the set of downlinktransmissions. In some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein, the dataindicator may be a new data indicator (NDI) that is included in theone-shot feedback report based on a configuration to include NDIinformation with the HARQ feedback.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of downlinktransmissions includes a set of downlink transmissions that may be eachassociated with a different HARQ process identification.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the one-shot feedback reportprovides HARQ feedback for each of a set of HARQ process IDs, and wherethe HARQ feedback is associated with one or more of a set of transportblocks, a set of component carriers, a set of code block groups, or anycombinations thereof.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the identifying theassociated HARQ feedback may include operations, features, means, orinstructions for identifying a codebook associated with theacknowledgment feedback for a set of feedback process identifications tobe reported in the one-shot feedback report. In some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein, a latest downlink transmission of the set of downlinktransmissions to be included in the one-shot feedback report may bedetermined based on a timing of downlink control information thatschedules the set of downlink transmissions, a latest downlinktransmission that meets a feedback timeline condition, or anycombinations thereof.

A method of wireless communications at a base station is described. Themethod may include configuring a UE for reporting HARQ feedback thatindicates successful or unsuccessful reception of one or more downlinktransmissions at the UE, where each downlink transmission has anassociated data indicator that indicates whether the downlinktransmission includes an initial transmission of downlink data or aretransmission of previously transmitted downlink data, and where theHARQ feedback indicates an acknowledgment/negative-acknowledgment andthe data indicator for each of the one or more downlink transmissions,transmitting a set of downlink transmissions to the UE, transmitting, tothe UE, downlink control information that indicates the UE is to providea one-shot feedback report for at least the one or more downlinktransmissions, and receiving, from the UE, the one-shot feedback reportthat indicates HARQ feedback for each of the one or more downlinktransmissions, where a default data indicator is included with the HARQfeedback for the one or more downlink transmissions in an absence ofscheduling information for a HARQ process identification of one or moreof the downlink transmissions.

An apparatus for wireless communications at a base station is described.The apparatus may include a processor, memory coupled with theprocessor, and instructions stored in the memory. The instructions maybe executable by the processor to cause the apparatus to configure a UEfor reporting HARQ feedback that indicates successful or unsuccessfulreception of one or more downlink transmissions at the UE, where eachdownlink transmission has an associated data indicator that indicateswhether the downlink transmission includes an initial transmission ofdownlink data or a retransmission of previously transmitted downlinkdata, and where the HARQ feedback indicates anacknowledgment/negative-acknowledgment and the data indicator for eachof the one or more downlink transmissions, transmit a set of downlinktransmissions to the UE, transmit, to the UE, downlink controlinformation that indicates the UE is to provide a one-shot feedbackreport for at least the one or more downlink transmissions, and receive,from the UE, the one-shot feedback report that indicates HARQ feedbackfor each of the one or more downlink transmissions, where a default dataindicator is included with the HARQ feedback for the one or moredownlink transmissions in an absence of scheduling information for aHARQ process identification of one or more of the downlinktransmissions.

Another apparatus for wireless communications at a base station isdescribed. The apparatus may include means for configuring a UE forreporting HARQ feedback that indicates successful or unsuccessfulreception of one or more downlink transmissions at the UE, where eachdownlink transmission has an associated data indicator that indicateswhether the downlink transmission includes an initial transmission ofdownlink data or a retransmission of previously transmitted downlinkdata, and where the HARQ feedback indicates anacknowledgment/negative-acknowledgment and the data indicator for eachof the one or more downlink transmissions, transmitting a set ofdownlink transmissions to the UE, transmitting, to the UE, downlinkcontrol information that indicates the UE is to provide a one-shotfeedback report for at least the one or more downlink transmissions, andreceiving, from the UE, the one-shot feedback report that indicates HARQfeedback for each of the one or more downlink transmissions, where adefault data indicator is included with the HARQ feedback for the one ormore downlink transmissions in an absence of scheduling information fora HARQ process identification of one or more of the downlinktransmissions.

A non-transitory computer-readable medium storing code for wirelesscommunications at a base station is described. The code may includeinstructions executable by a processor to configure a UE for reportingHARQ feedback that indicates successful or unsuccessful reception of oneor more downlink transmissions at the UE, where each downlinktransmission has an associated data indicator that indicates whether thedownlink transmission includes an initial transmission of downlink dataor a retransmission of previously transmitted downlink data, and wherethe HARQ feedback indicates an acknowledgment/negative-acknowledgmentand the data indicator for each of the one or more downlinktransmissions, transmit a set of downlink transmissions to the UE,transmit, to the UE, downlink control information that indicates the UEis to provide a one-shot feedback report for at least the one or moredownlink transmissions, and receive, from the UE, the one-shot feedbackreport that indicates HARQ feedback for each of the one or more downlinktransmissions, where a default data indicator is included with the HARQfeedback for the one or more downlink transmissions in an absence ofscheduling information for a HARQ process identification of one or moreof the downlink transmissions.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the one-shot feedback reportmay be transmitted with an uplink transmission of the UE, and where onlythe one-shot feedback report is provided with the uplink transmissionirrespective of whether a HARQ reporting timeline of one or more othertypes of HARQ feedback corresponds to a timing of the uplinktransmission. In some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein, the one-shotfeedback report includes one or more of acknowledgment (ACK)indications, negative acknowledgment (NACK) indications, the dataindicator, or combinations thereof, that may be each associated with acorresponding HARQ process identification (ID) for a downlinktransmission of the set of downlink transmissions. In some examples ofthe method, apparatuses, and non-transitory computer-readable mediumdescribed herein, the data indicator may be a new data indicator (NDI).

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the set of downlinktransmissions includes a set of downlink transmissions that are eachassociated with a different HARQ process ID. In some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein, the one-shot feedback report provides HARQ feedbackfor each of a set of HARQ process IDs, and where the HARQ feedback isassociated with one or more of a set of transport blocks, a set ofcomponent carriers, a set of code block groups, or any combinationsthereof.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the default data indicatormay be reported by the UE for a first feedback process identificationfor which the UE has not received scheduling information that indicatesthe first feedback process identification is to be used to indicatefeedback for one of the subset of the downlink transmissions. In someexamples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the default data indicatormay be applied at a polar decoder as a frozen bit to assist decoding ofthe feedback report when scheduling information that indicates the firstfeedback process identification has not been transmitted to the UE.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, a latest downlinktransmission of the set of downlink transmissions to be included in theone-shot feedback report may be determined based on a timing of downlinkcontrol information that schedules the set of downlink transmissions, alatest downlink transmission that meets a feedback timeline condition,or any combinations thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communicationsthat supports acknowledgment feedback techniques in shared radiofrequency spectrum in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a portion of a wireless communicationssystem that supports acknowledgment feedback techniques in shared radiofrequency spectrum in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of ACK feedback timelines that supportacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure.

FIG. 4 illustrates an example of feedback information that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure.

FIG. 5 illustrates an example of multiplexed feedback reports thatsupports acknowledgment feedback techniques in shared radio frequencyspectrum in accordance with aspects of the present disclosure.

FIG. 6 illustrates an example of feedback timing that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure.

FIG. 7 illustrates an example of feedback timing that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure.

FIGS. 8 and 9 show block diagrams of devices that support acknowledgmentfeedback techniques in shared radio frequency spectrum in accordancewith aspects of the present disclosure.

FIG. 10 shows a block diagram of a communications manager that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure.

FIG. 11 shows a diagram of a system including a device that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure.

FIGS. 12 and 13 show block diagrams of devices that supportacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure.

FIG. 14 shows a block diagram of a communications manager that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure.

FIG. 15 shows a diagram of a system including a device that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure.

FIGS. 16 through 23 show flowcharts illustrating methods that supportacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure.

DETAILED DESCRIPTION

The described aspects of the disclosure relate to improved methods,systems, devices, or apparatuses that facilitate feedback fortransmissions or retransmissions, such as hybrid automatic repeatrequest (HARQ) acknowledgment/negative-acknowledgment (ACK/NACK)feedback reports. In some examples, the techniques described hereinenable efficient group or one-shot HARQ feedback reporting, in whichfeedback for a number of different downlink transmissions may beprovided by a user equipment (UE) to a base station in a wirelesscommunications system.

In some cases, a wireless communications system may further supportcommunications in an unlicensed spectrum (e.g., a shared radio frequencyspectrum band), licensed spectrum, or a combination of licensed andunlicensed spectrums. In such systems, one or more transmissions may notbe successfully received due to interference from a hidden node, or maynot be transmitted due to LBT failure. Accordingly, the HARQ feedbackmay not include feedback for one or more of the missed HARQ process IDs(e.g., due to interference, LBT failure, etc.). One-shot or group HARQfeedback reports may be used in such cases, which allow the UE totransmit feedback for all of the HARQ processes that are configured atthe UE. The base station may trigger the one-shot HARQ feedback in adownlink message (e.g., downlink or uplink grant), in a separatedownlink message (e.g., a separate DCI), or in a group common DCIprovided to a number of UEs. If the HARQ feedback for a particular HARQprocess ID is ready when the trigger is received, the UE may transmitappropriate HARQ feedback based on decoding results. Alternatively, ifthe HARQ feedback for a particular HARQ process ID is not ready when thetrigger is received (e.g., based on an associated feedback timeline),the UE may transmit a previous value or a default value (e.g., a NACK)for the particular HARQ process.

In some cases, a base station may trigger a one-shot feedback reportthat includes a subset of less than all of the HARQ feedback that isavailable at the UE to provide in a report. For example, HARQ feedbackassociated with a particular component carrier (CC) of a set of CCs maybe requested by the base station and transmitted by the UE. In somecases, the subset of HARQ feedback may be associated with a transportblock, one or more HARQ process IDs, one or more code block groups(CBGs), a particular new data indicator (NDI) state, one or more CCs, orcombinations thereof. The base station may indicate the subset of HARQfeedback in downlink control information (DCI) that is transmitted totrigger the UE to transmit the one-shot feedback. In some cases, thesignaling in the DCI may be explicit (e.g., in one or more DCIinformation fields) or may be implicit (e.g., based on a CC thattransmits the DCI or CCs that are scheduled by the DCI). Such techniquesmay allow for more efficient use of resources by reducing an amount ofdata transmitted in such one-shot HARQ feedback reports (e.g., HARQfeedback for only a CC which receives interference or failed a LBTprocedure).

In some cases, HARQ feedback may include an indication of an ACK or NACKmay be provided along with information related to a NDI associated withthe downlink transmission for which the feedback is provided. In somecases, a tri-state indication may be used to indicate, for a particularHARQ ID, an ACK for a first NDI, an ACK for a second NDI, or a NACK. Insome cases, the base station may configure one or more codebooks thatprovide bit sequences for different combinations of feedback indicationsfor each HARQ ID. Such a tri-state indications may allow for reducedoverhead through transmission of fewer bits. Further, by providing anindication of the NDI associated with the feedback information mayreduce ambiguity that may result from a UE not receiving schedulinginformation that may indicate a different NDI.

In some cases, regular feedback reports and group one-shot feedbackreports may be multiplexed by a UE and transmitted to the base station.In some cases, regularly scheduled feedback (e.g., based on predefineduplink control information resources associated with scheduled downlinktransmissions to a UE) may be provided, that may be concatenated with aone-shot report. In some cases, one or more downlink transmissions mayhave HARQ feedback reported in both reports (e.g., one HARQ ID may bereported in each feedback report). Such techniques may provide certaintyrelated to size and content of each HARQ feedback report.

Further, in some cases, a last downlink transmission to be included in aone-shot feedback report may be determined based on a receipt time ofscheduling information or an HARQ feedback timeline. For example, if afirst downlink transmission having an associated first HARQ ID istransmitted before a feedback timeline that is based on a processingtime prior to transmission of the HARQ report, it will be included inthe HARQ report, and if a second downlink transmission having anassociated second HARQ ID is transmitted after the feedback timeline, itwill not be included in the HARQ report. Such a timeline baseddetermination for including feedback information in a feedback reportmay provide defined rules for including certain HARQ feedback in afeedback report and may reduce ambiguity in expected information in suchreports. It is to be noted that various techniques detailed herein maybe implemented in conjunction with other of the disclosed techniques, orindependently of other of the described techniques.

Aspects of the disclosure are initially described in the context of awireless communications system. Additional aspects of the disclosure arethen described with respect to group or one-shot ACK feedback schemes.Aspects of the disclosure are further illustrated by and described withreference to apparatus diagrams, system diagrams, and flowcharts thatrelate to acknowledgment feedback techniques in shared radio frequencyspectrum.

FIG. 1 illustrates an example of a wireless communications system 100that supports acknowledgment feedback techniques in shared radiofrequency spectrum in accordance with aspects of the present disclosure.The wireless communications system 100 includes base stations 105, UEs115, and a core network 130. In some examples, the wirelesscommunications system 100 may be a Long Term Evolution (LTE) network, anLTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR)network. In some cases, wireless communications system 100 may supportenhanced broadband communications, ultra-reliable (e.g., missioncritical) communications, low latency communications, or communicationswith low-cost and low-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Base stations 105 described herein mayinclude or may be referred to by those skilled in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB orgiga-NodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or some other suitable terminology. Wirelesscommunications system 100 may include base stations 105 of differenttypes (e.g., macro or small cell base stations). The UEs 115 describedherein may be able to communicate with various types of base stations105 and network equipment including macro eNBs, small cell eNBs, gNBs,relay base stations, and the like.

Each base station 105 may be associated with a particular geographiccoverage area 110 in which communications with various UEs 115 issupported. Each base station 105 may provide communication coverage fora respective geographic coverage area 110 via communication links 125,and communication links 125 between a base station 105 and a UE 115 mayutilize one or more carriers. Communication links 125 shown in wirelesscommunications system 100 may include uplink transmissions from a UE 115to a base station 105, or downlink transmissions from a base station 105to a UE 115. Downlink transmissions may also be called forward linktransmissions while uplink transmissions may also be called reverse linktransmissions.

The geographic coverage area 110 for a base station 105 may be dividedinto sectors making up a portion of the geographic coverage area 110,and each sector may be associated with a cell. For example, each basestation 105 may provide communication coverage for a macro cell, a smallcell, a hot spot, or other types of cells, or various combinationsthereof. In some examples, a base station 105 may be movable andtherefore provide communication coverage for a moving geographiccoverage area 110. In some examples, different geographic coverage areas110 associated with different technologies may overlap, and overlappinggeographic coverage areas 110 associated with different technologies maybe supported by the same base station 105 or by different base stations105. The wireless communications system 100 may include, for example, aheterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different typesof base stations 105 provide coverage for various geographic coverageareas 110.

The term “cell” refers to a logical communication entity used forcommunication with a base station 105 (e.g., over a carrier), and may beassociated with an identifier for distinguishing neighboring cells(e.g., a physical cell identifier (PCID), a virtual cell identifier(VCID)) operating via the same or a different carrier. In some examples,a carrier may support multiple cells, and different cells may beconfigured according to different protocol types (e.g., machine-typecommunication (MTC), narrowband Internet-of-Things (NB-IoT), enhancedmobile broadband (eMBB), or others) that may provide access fordifferent types of devices. In some cases, the term “cell” may refer toa portion of a geographic coverage area 110 (e.g., a sector) over whichthe logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile device, a wireless device, a remote device, ahandheld device, or a subscriber device, or some other suitableterminology, where the “device” may also be referred to as a unit, astation, a terminal, or a client. A UE 115 may also be a personalelectronic device such as a cellular phone, a personal digital assistant(PDA), a tablet computer, a laptop computer, or a personal computer. Insome examples, a UE 115 may also refer to a wireless local loop (WLL)station, an Internet of Things (IoT) device, an Internet of Everything(IoE) device, or an MTC device, or the like, which may be implemented invarious articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines (e.g., via Machine-to-Machine (M2M) communication). M2Mcommunication or MTC may refer to data communication technologies thatallow devices to communicate with one another or a base station 105without human intervention. In some examples, M2M communication or MTCmay include communications from devices that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application. Some UEs 115 may be designed to collectinformation or enable automated behavior of machines. Examples ofapplications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reducepower consumption, such as half-duplex communications (e.g., a mode thatsupports one-way communication via transmission or reception, but nottransmission and reception simultaneously). In some examples half-duplexcommunications may be performed at a reduced peak rate. Other powerconservation techniques for UEs 115 include entering a power saving“deep sleep” mode when not engaging in active communications, oroperating over a limited bandwidth (e.g., according to narrowbandcommunications). In some cases, UEs 115 may be designed to supportcritical functions (e.g., mission critical functions), and a wirelesscommunications system 100 may be configured to provide ultra-reliablecommunications for these functions.

In some cases, a UE 115 may also be able to communicate directly withother UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device(D2D) protocol). One or more of a group of UEs 115 utilizing D2Dcommunications may be within the geographic coverage area 110 of a basestation 105. Other UEs 115 in such a group may be outside the geographiccoverage area 110 of a base station 105, or be otherwise unable toreceive transmissions from a base station 105. In some cases, groups ofUEs 115 communicating via D2D communications may utilize a one-to-many(1:M) system in which each UE 115 transmits to every other UE 115 in thegroup. In some cases, a base station 105 facilitates the scheduling ofresources for D2D communications. In other cases, D2D communications arecarried out between UEs 115 without the involvement of a base station105.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (e.g., via an S1, N2, N3, orother interface). Base stations 105 may communicate with one anotherover backhaul links 134 (e.g., via an X2, Xn, or other interface) eitherdirectly (e.g., directly between base stations 105) or indirectly (e.g.,via core network 130).

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC), which may include at least one mobilitymanagement entity (MME), at least one serving gateway (S-GW), and atleast one Packet Data Network (PDN) gateway (P-GW). The MME may managenon-access stratum (e.g., control plane) functions such as mobility,authentication, and bearer management for UEs 115 served by basestations 105 associated with the EPC. User IP packets may be transferredthrough the S-GW, which itself may be connected to the P-GW. The P-GWmay provide IP address allocation as well as other functions. The P-GWmay be connected to the network operators IP services. The operators IPservices may include access to the Internet, Intranet(s), an IPMultimedia Subsystem (IMS), or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, mayinclude subcomponents such as an access network entity, which may be anexample of an access node controller (ANC). Each access network entitymay communicate with UEs 115 through a number of other access networktransmission entities, which may be referred to as a radio head, a smartradio head, or a transmission/reception point (TRP). In someconfigurations, various functions of each access network entity or basestation 105 may be distributed across various network devices (e.g.,radio heads and access network controllers) or consolidated into asingle network device (e.g., a base station 105).

Wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 megahertz (MHz) to 300gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known asthe ultra-high frequency (UHF) region or decimeter band, since thewavelengths range from approximately one decimeter to one meter inlength. UHF waves may be blocked or redirected by buildings andenvironmental features. However, the waves may penetrate structuressufficiently for a macro cell to provide service to UEs 115 locatedindoors. Transmission of UHF waves may be associated with smallerantennas and shorter range (e.g., less than 100 km) compared totransmission using the smaller frequencies and longer waves of the highfrequency (HF) or very high frequency (VHF) portion of the spectrumbelow 300 MHz.

Wireless communications system 100 may also operate in a super highfrequency (SHF) region using frequency bands from 3 GHz to 30 GHz, alsoknown as the centimeter band. The SHF region includes bands such as the5 GHz industrial, scientific, and medical (ISM) bands, which may be usedopportunistically by devices that may be capable of toleratinginterference from other users.

Wireless communications system 100 may also operate in an extremely highfrequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz),also known as the millimeter band. In some examples, wirelesscommunications system 100 may support millimeter wave (mmW)communications between UEs 115 and base stations 105, and EHF antennasof the respective devices may be even smaller and more closely spacedthan UHF antennas. In some cases, this may facilitate use of antennaarrays within a UE 115. However, the propagation of EHF transmissionsmay be subject to even greater atmospheric attenuation and shorter rangethan SHF or UHF transmissions. Techniques disclosed herein may beemployed across transmissions that use one or more different frequencyregions, and designated use of bands across these frequency regions maydiffer by country or regulating body.

In some cases, wireless communications system 100 may utilize bothlicensed and unlicensed or shared radio frequency spectrum bands. Forexample, wireless communications system 100 may employ License AssistedAccess (LAA), LTE-Unlicensed (LTE-U) radio access technology, or NRtechnology in an unlicensed band (NR-U) such as the 5 GHz ISM band. Whenoperating in unlicensed or shared radio frequency spectrum bands,wireless devices such as base stations 105 and UEs 115 may employlisten-before-talk (LBT) procedures to ensure a frequency channel isclear before transmitting data. In some cases, operations in unlicensedbands may be based on a carrier aggregation configuration in conjunctionwith component carriers operating in a licensed band (e.g., LAA).Operations in unlicensed spectrum may include downlink transmissions,uplink transmissions, peer-to-peer transmissions, or a combination ofthese. Duplexing in unlicensed spectrum may be based on frequencydivision duplexing (FDD), time division duplexing (TDD), or acombination of both.

In some examples, base station 105 or UE 115 may be equipped withmultiple antennas, which may be used to employ techniques such astransmit diversity, receive diversity, multiple-input multiple-output(MIMO) communications, or beamforming. For example, wirelesscommunications system 100 may use a transmission scheme between atransmitting device (e.g., a base station 105) and a receiving device(e.g., a UE 115), where the transmitting device is equipped withmultiple antennas and the receiving device is equipped with one or moreantennas. MIMO communications may employ multipath signal propagation toincrease the spectral efficiency by transmitting or receiving multiplesignals via different spatial layers, which may be referred to asspatial multiplexing. The multiple signals may, for example, betransmitted by the transmitting device via different antennas ordifferent combinations of antennas. Likewise, the multiple signals maybe received by the receiving device via different antennas or differentcombinations of antennas. Each of the multiple signals may be referredto as a separate spatial stream, and may carry bits associated with thesame data stream (e.g., the same codeword) or different data streams.Different spatial layers may be associated with different antenna portsused for channel measurement and reporting. MIMO techniques includesingle-user MIMO (SU-MIMO) where multiple spatial layers are transmittedto the same receiving device, and multiple-user MIMO (MU-MIMO) wheremultiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (e.g., a base station 105 or a UE 115) to shape orsteer an antenna beam (e.g., a transmit beam or receive beam) along aspatial path between the transmitting device and the receiving device.Beamforming may be achieved by combining the signals communicated viaantenna elements of an antenna array such that signals propagating atparticular orientations with respect to an antenna array experienceconstructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying certain amplitude and phase offsets to signals carried via eachof the antenna elements associated with the device. The adjustmentsassociated with each of the antenna elements may be defined by abeamforming weight set associated with a particular orientation (e.g.,with respect to the antenna array of the transmitting device orreceiving device, or with respect to some other orientation).

In one example, a base station 105 may use multiple antennas or antennaarrays to conduct beamforming operations for directional communicationswith a UE 115. For instance, some signals (e.g. synchronization signals,reference signals, beam selection signals, or other control signals) maybe transmitted by a base station 105 multiple times in differentdirections, which may include a signal being transmitted according todifferent beamforming weight sets associated with different directionsof transmission. Transmissions in different beam directions may be usedto identify (e.g., by the base station 105 or a receiving device, suchas a UE 115) a beam direction for subsequent transmission and/orreception by the base station 105.

In some cases, the antennas of a base station 105 or UE 115 may belocated within one or more antenna arrays, which may support MIMOoperations, or transmit or receive beamforming. For example, one or morebase station antennas or antenna arrays may be co-located at an antennaassembly, such as an antenna tower. In some cases, antennas or antennaarrays associated with a base station 105 may be located in diversegeographic locations. A base station 105 may have an antenna array witha number of rows and columns of antenna ports that the base station 105may use to support beamforming of communications with a UE 115.Likewise, a UE 115 may have one or more antenna arrays that may supportvarious MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-basednetwork that operate according to a layered protocol stack. In the userplane, communications at the bearer or Packet Data Convergence Protocol(PDCP) layer may be IP-based. A Radio Link Control (RLC) layer mayperform packet segmentation and reassembly to communicate over logicalchannels. A Medium Access Control (MAC) layer may perform priorityhandling and multiplexing of logical channels into transport channels.The MAC layer may also use hybrid automatic repeat request (HARD) toprovide retransmission at the MAC layer to improve link efficiency. Inthe control plane, the Radio Resource Control (RRC) protocol layer mayprovide establishment, configuration, and maintenance of an RRCconnection between a UE 115 and a base station 105 or core network 130supporting radio bearers for user plane data. At the Physical layer,transport channels may be mapped to physical channels.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit, which may, for example, refer to a sampling period ofT_(s)=1/30,720,000 seconds. Time intervals of a communications resourcemay be organized according to radio frames each having a duration of 10milliseconds (ms), where the frame period may be expressed asT_(f)=307,200 T_(s). The radio frames may be identified by a systemframe number (SFN) ranging from 0 to 1023. Each frame may include 10subframes numbered from 0 to 9, and each subframe may have a duration of1 ms. A subframe may be further divided into 2 slots each having aduration of 0.5 ms, and each slot may contain 6 or 7 modulation symbolperiods (e.g., depending on the length of the cyclic prefix prepended toeach symbol period). Excluding the cyclic prefix, each symbol period maycontain 2048 sampling periods. In some cases, a subframe may be thesmallest scheduling unit of the wireless communications system 100, andmay be referred to as a transmission time interval (TTI). In othercases, a smallest scheduling unit of the wireless communications system100 may be shorter than a subframe or may be dynamically selected (e.g.,in bursts of shortened TTIs (sTTIs) or in selected component carriersusing sTTIs).

In some wireless communications systems, a slot may further be dividedinto multiple mini-slots containing one or more symbols. In someinstances, a symbol of a mini-slot or a mini-slot may be the smallestunit of scheduling. Each symbol may vary in duration depending on thesubcarrier spacing or frequency band of operation, for example. Further,some wireless communications systems may implement slot aggregation inwhich multiple slots or mini-slots are aggregated together and used forcommunication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resourceshaving a defined physical layer structure for supporting communicationsover a communication link 125. For example, a carrier of a communicationlink 125 may include a portion of a radio frequency spectrum band thatis operated according to physical layer channels for a given radioaccess technology. Each physical layer channel may carry user data,control information, or other signaling. A carrier may be associatedwith a pre-defined frequency channel (e.g., an evolved universal mobiletelecommunication system terrestrial radio access (E-UTRA) absoluteradio frequency channel number (EARFCN)), and may be positionedaccording to a channel raster for discovery by UEs 115. Carriers may bedownlink or uplink (e.g., in an FDD mode), or be configured to carrydownlink and uplink communications (e.g., in a TDD mode). In someexamples, signal waveforms transmitted over a carrier may be made up ofmultiple sub-carriers (e.g., using multi-carrier modulation (MCM)techniques such as orthogonal frequency division multiplexing (OFDM) ordiscrete Fourier transform spread OFDM (DFT-S-OFDM)).

The organizational structure of the carriers may be different fordifferent radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR).For example, communications over a carrier may be organized according toTTIs or slots, each of which may include user data as well as controlinformation or signaling to support decoding the user data. A carriermay also include dedicated acquisition signaling (e.g., synchronizationsignals or system information, etc.) and control signaling thatcoordinates operation for the carrier. In some examples (e.g., in acarrier aggregation configuration), a carrier may also have acquisitionsignaling or control signaling that coordinates operations for othercarriers.

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a downlink carrier, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, controlinformation transmitted in a physical control channel may be distributedbetween different control regions in a cascaded manner (e.g., between acommon control region or common search space and one or more UE-specificcontrol regions or UE-specific search spaces).

A carrier may be associated with a particular bandwidth of the radiofrequency spectrum, and in some examples the carrier bandwidth may bereferred to as a “system bandwidth” of the carrier or the wirelesscommunications system 100. For example, the carrier bandwidth may be oneof a number of predetermined bandwidths for carriers of a particularradio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz). Insome examples, each served UE 115 may be configured for operating overportions or all of the carrier bandwidth. In other examples, some UEs115 may be configured for operation using a narrowband protocol typethat is associated with a predefined portion or range (e.g., set ofsubcarriers or RBs) within a carrier (e.g., “in-band” deployment of anarrowband protocol type).

In a system employing MCM techniques, a resource element may consist ofone symbol period (e.g., a duration of one modulation symbol) and onesubcarrier, where the symbol period and subcarrier spacing are inverselyrelated. The number of bits carried by each resource element may dependon the modulation scheme (e.g., the order of the modulation scheme).Thus, the more resource elements that a UE 115 receives and the higherthe order of the modulation scheme, the higher the data rate may be forthe UE 115. In MIMO systems, a wireless communications resource mayrefer to a combination of a radio frequency spectrum resource, a timeresource, and a spatial resource (e.g., spatial layers), and the use ofmultiple spatial layers may further increase the data rate forcommunications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations105 or UEs 115) may have a hardware configuration that supportscommunications over a particular carrier bandwidth, or may beconfigurable to support communications over one of a set of carrierbandwidths. In some examples, the wireless communications system 100 mayinclude base stations 105 and/or UEs 115 that support simultaneouscommunications via carriers associated with more than one differentcarrier bandwidth.

Wireless communications system 100 may support communication with a UE115 on multiple cells or carriers, a feature which may be referred to ascarrier aggregation or multi-carrier operation. A UE 115 may beconfigured with multiple downlink component carriers and one or moreuplink component carriers according to a carrier aggregationconfiguration. Carrier aggregation may be used with both FDD and TDDcomponent carriers.

In some cases, UEs 115 and base stations 105 may support retransmissionsof data to increase the likelihood that data is received successfully.HARQ feedback such as discussed herein is one technique of increasingthe likelihood that data is received correctly over a communication link125. HARQ may include a combination of error detection (e.g., using acyclic redundancy check (CRC)), forward error correction (FEC), andretransmission (e.g., automatic repeat request (ARQ)). HARQ may improvethroughput at the MAC layer in poor radio conditions (e.g.,signal-to-noise conditions). In some cases, a wireless device maysupport same-slot HARQ feedback, where the device may provide HARQfeedback in a specific slot for data received in a previous symbol inthe slot. In other cases, the device may provide HARQ feedback in asubsequent slot, or according to some other time interval. In somecases, one-shot HARQ feedback may be enabled, in which a base station105 may trigger a one-shot HARQ report to prompt a UE 115 to transmitHARQ feedback for each of its configured HARQ process IDs. Varioustechniques described herein enable efficient one-shot HARQ feedbackreporting, in which feedback for a number of different downlinktransmissions may be provided by a UE 115 to a base station 105.

FIG. 2 illustrates an example of a wireless communications system 200that supports acknowledgment feedback techniques in shared radiofrequency spectrum in accordance with aspects of the present disclosure.In some examples, wireless communications system 200 may implementaspects of wireless communications system 100. Wireless communicationssystem 200 may include a base station 105-a and a UE 115-a, which may beexamples of corresponding base stations 105 and UEs 115 as describedwith reference to FIG. 1.

As described herein, base station 105-a and UE 115-a may communicate inan unlicensed spectrum (e.g., a shared radio frequency spectrum band)and may employ HARQ feedback techniques to indicate whether data hasbeen received correctly at UE 115-a. For example, base station 105-a maytransmit one or more downlink messages to UE 115-a on resources of acarrier 205. Accordingly, UE 115-a may transmit an indication of whetherthe one or more downlink messages were received and decoded correctly onresources of a carrier 210. In some cases, carriers 205 and 210 may bethe same carrier. In some cases, carriers 205 and 210 may be componentcarriers (CCs), and a number of different CCs may be used forcommunications between the UE 115-a and the base station 105-a. In thisexample, base station 105-a may transmit a one-shot HARQ feedbacktrigger 215 on carrier 205, and UE 115-a responds with feedback report220 on carrier 210. One-shot HARQ feedback trigger 215 may be includedin a downlink or uplink grant (e.g., downlink message such as PDCCH), orUE 115-a may be explicitly triggered to transmit feedback report 220(e.g., in a separate DCI message).

When one-shot HARQ feedback trigger 215 is present, UE 115-a may beindicated, by base station 105-a, to provide the feedback report 220based on one or more configured HARQ processes for UE 115-a. Forexample, the base station 105-a may configure the UE 115-a with eightHARQ process IDs, and each transport block (TB) transmitted by the basestation 105-a may have an associated HARQ ID. The UE 115-a may use theindicated HARQ ID to provide feedback that indicates to the base station105-a whether the associated TB is successfully or unsuccessfullyreceived. In some cases, scheduling information for a downlinktransmission may also include a NDI associated with the downlinktransmission (e.g., a scheduled TB), which may indicate if thetransmission is an initial transmission of data for the TB or aretransmission of data for the TB (that may then be used insoft-combining techniques).

The feedback report 220 may indicate HARQ feedback for all or a subsetof the configured HARQ processes for UE 115-a. In some cases, feedbackinformation each HARQ ID may include a corresponding code block group(CBG) or TB level ACK bits based on its configuration. In some cases, UE115-a may be explicitly triggered by one-shot HARQ feedback trigger 215for the feedback report 220 along with an indication of a particulartransmission time interval (e.g., slot, symbol, etc.) for transmittingthe feedback report 220. UE 115-a may populate the fields for feedbackreport 220 based on decoding results for the corresponding HARQ process(e.g., ACK if successfully decoded, NACK if unsuccessfullyreceived/decoded). In some cases, UE 115-a may populate thecorresponding fields for feedback report 220 with previous values forthe HARQ process or with a default value (e.g., ACK, NACK, NDI, or anycombinations thereof). Base station 105-a may accordingly interpret ifthe fields for each HARQ process are based on decoding results, previousvalues, or default values. As will be discussed in more detail withreference to FIGS. 3 through 7, in various examples the feedback report220 may include HARQ feedback for one or more subsets of HARQinformation, which may be multiplexed with one or more other reports,may indicate feedback and an associated NDI, may include HARQ feedbackfor HARQ IDs based on timelines associated with scheduling andtransmitting reports, or any combinations thereof.

FIG. 3 illustrates an example of ACK feedback timelines 300 that supportacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. In some examples, ACKfeedback timelines 300 may implement aspects of wireless communicationssystem 100 or 200. In this example, a UE (e.g., a UE 115 of FIG. 1 or 2)and a base station (e.g., a base station 105 of FIG. 1 or 2) mayestablish multiple CCs for downlink transmissions, uplink transmissions,or both. In the example of FIG. 3, a first CC 305 and a second CC 310may be configured.

The base station may transmit a first subset of downlink transmissions315 via the first CC 305, which the UE may attempt to receive anddecode. In this example, the UE may have eight HARQ processesconfigured, having HARQ IDs 0 through 7. Further, scheduling informationprovided for downlink transmissions may include a NDI for eachtransmission, which the UE may use in decoding the associatedtransmissions. In this example, downlink transmissions (e.g., TBs)associated with HARQ IDs 0 through 3, each having an NDI of zero, may bescheduled as the first subset of downlink transmissions 315. Further, asecond subset of downlink transmissions 325 may be scheduled for HARQIDs 0 through 3 that each have an NDI of one. Similarly, on the secondCC 310, a third subset of downlink transmissions 335 may have HARQ IDs 4through 7 each having an NDI of 0, and a fourth subset of downlinktransmissions 345 may have HARQ IDs 4 through 7 each having an NDI of 1.It is noted that this example is provided for purposes of discussion andillustration, and numerous different examples of downlink transmissionsmay be used to implement techniques discussed herein.

In some cases, the UE may be configured to provide HARQ feedback 320associated with the first subset of downlink transmissions 315 usinguplink resources that are predetermined or provided in schedulinginformation associated with the first subset of downlink transmissions315. In this example, the UE may not successfully transmit the HARQfeedback 320, due to a failed LBT or interference from anothertransmitter, for example. In this example, the base station may providea one-shot HARQ trigger 330 to the UE to trigger a one-shot group HARQfeedback report 350. The UE may also be configured to provide HARQfeedback 340 and 355 for the third subset of downlink transmissions 335and fourth subset of downlink transmissions 345, respectively. The basestation may transmit one-shot HARQ trigger 330, in this example, whichmay trigger the UE to transmit group HARQ feedback report 350.

In some cases, the one-shot HARQ trigger 330 may indicate that the UE isto transmit HARQ feedback for each configured HARQ process ID (e.g., forHARQ IDs 0 through 7 in the example of FIG. 3). Further, since differenttransmissions may have different NDIs, the UE may also provide anindication of which NDI is associated each feedback indication. In caseswhere the group HARQ feedback report 350 includes all of suchinformation, the size of the report can become relatively large (e.g.,five CCs may be configured, each having 16 HARQ IDs, that can correspondto 2 TBs, resulting in a payload size of 5*16*2 bits for A/N bits and5*16*2 bits for NDIs, and CBG-based feedback can further increase thepayload). Further, in some cases, such as in the example of FIG. 3, onlya subset of transmissions may have missing feedback, such as thefeedback from HARQ feedback report 320 associated with the first subsetof downlink transmissions 315. In such cases, the one-shot HARQ trigger330 may indicate a subset of HARQ information that is to be reported inthe group HARQ feedback report 350.

In some cases, one or more fields may be included in a DCI that includesthe one-shot HARQ trigger 330, which may indicate the particular subsetof HARQ feedback is to be reported by the UE. Further, in some cases adownlink assignment indicator (DAI) field in DCI may be reused toprovide an indication of one or more subsets of HARQ feedback that areto be reported. Such a DAI field may be reused for one-shot triggeringdue to the DAI field being used to indicate regular feedback resources,rather than one-shot feedback information, and thus a DCI containing aone-shot HARQ trigger 330 may re-purpose this field. In some examples,the DCI may indicate request for all CCs or a subset of CCs, which maybe explicitly indicated in the DCI or be implicit. In cases where therequested CCs are implicit, the subset of CCs to be reported may bebased on, for example, a scheduling CC (e.g., only HARQ feedback of theCC that the DCI is detected on is requested), or a scheduled CC (e.g.,only HARQ feedback of the scheduled cell is requested, in which case theDCI requesting the one-shot HARQ feedback may also schedule PDSCH in aCC that may be different than the CC carrying the DCI). Further, for agiven CC or for all CCs, the DCI may indicate a request for allconfigured HARQ IDs or a subset of them (e.g., DCI can indicate all ofconfigured HARQ IDs or a first half of configured HARQ IDs through a onebit indication in the DCI). In some cases, requesting only a first halfof the configured HARQ IDs may be desirable because the base station mayonly rarely use HARQ IDs in the second half, or the base station may beaware that no HARQ IDs of the second half of HARQ IDs have been used fora particular CC. Additionally, in some cases, the DCI can indicatewhether to include an indication of NDIs with the HARQ feedback, and theUE may use a codebook to determine the HARQ feedback based on whetherNDIs are to be indicated or not. Additional details related to NDIindications are discussed with reference to FIG. 4. Further, in somecases the DCI may indicate whether to include CBG-based HARQ feedback ornot, which may apply to all CCs or HARQ IDs, or can be controlledseparately for a group of CCs or HARQ IDs. In some cases, the basestation may configure the UE (e.g., during a RRC connectionestablishment or reestablishment) with what type of information may berequested for a one-shot HARQ feedback report.

FIG. 4 illustrates an example of feedback information 400 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. In some examples,feedback information 400 may implement aspects of wirelesscommunications system 100 or 200. In this example, a UE (e.g., a UE 115of FIG. 1 or 2) and a base station (e.g., a base station 105 of FIG. 1or 2) may establish multiple CCs for downlink transmissions, uplinktransmissions, or both. In the example of FIG. 4, a first CC 405 isillustrated, with the understanding that one or more other CCs may bepresent.

The base station may transmit a first subset of downlink transmissions415 via the first CC 405, which the UE may attempt to receive anddecode. In this example, the UE may have eight HARQ processesconfigured, having HARQ IDs 0 through 7. Further, scheduling informationprovided for downlink transmissions may include a NDI for eachtransmission, which the UE may use in decoding the associatedtransmissions. In this example, downlink transmissions (e.g., TBs)associated with HARQ IDs 0 through 3, each having an NDI of zero, may bescheduled as the first subset of downlink transmissions 415. Further, asecond subset of downlink transmissions 425 may be scheduled for HARQIDs 4, 5, and 6 that each have a NDI of 0 and for HARQ ID 1 with a NDIof 1. In this example, HARQ feedback 420 may not be successfullytransmitted (e.g., due to LBT failure) or received (e.g., due tointerference), and the base station may transmit a one-shot HARQ trigger430 to trigger group HARQ feedback report 450. The group HARQ feedbackreport 450 may be triggered for a subset of downlink transmissions, asdiscussed herein.

In this example, the group HARQ feedback report 450 may include HARQfeedback information for each of the configured HARQ IDs, which in thisexample are HARQ IDs 0 through 7. Further, in this example, the groupHARQ feedback report 450 may be configured to include NDI informationassociated with a HARQ ID in order to reduce ambiguity associated withthe HARQ feedback. For example, in HARQ ID 1 in this case has NDI of 0and NDI of 1 for different downlink transmissions. Thus, if an ACK isreported for HARQ ID 1, there may be ambiguity regarding which NDI theACK is associated with. Further, if none of the HARQ ID 1 transmissionsare successfully received, a single NACK may indicate thatretransmission is needed, because the base station may assume that NACKis for the latest NDI.

In this example, NDI compression may be achieved through a three-stateindicator. Thus, instead of 2-bits per HARQ ID per TB (i.e., one bit forACK/NNACK plus one bit for NDI), a three state feedback indication maybe provided that indicates NACK, ACK with NDI=0, or ACK with NDI=1. Sucha tri-state indication may reduce the payload size of the feedbackreport. For example, if 16 HARQ IDs are configured, this results in 26bits being needed to report the HARQ feedback (i.e., log 2(3¹⁶)=26 bits)rather than 32 bits for a four bit indicator. In some cases, a codebookmay be configured that provides bit sequences for different combinationsof feedback for the configured number of HARQ IDs, and the UE may selectthe 26 bit HARQ feedback based on a mapping between the indicators foreach HARQ ID and the bit sequence from the codebook.

Further, in some cases, the UE may not be scheduled for transmissionsfor a particular HARQ ID, and in such cases the one-shot feedback reportmay include a default value (e.g., NDI=0) for the NDI associated withsuch a HARQ ID, along with the ACK/NACK bit (e.g., indicating NACK). Insuch cases, the base station, if such a HARQ ID had been scheduled, mayreceive the NACK and determine that the scheduling information and/ortransmission was not successfully received, and if such a HARQ ID hasnot been scheduled may know the value for that particular bit in thefeedback report. In some cases, if the particular HARQ process has notbeen used, the base station may use this known bit value to assist indecoding (e.g., a frozen bit may be provided to a Polar decoder to helpimprove the performance and efficiency of decoding the feedback report).Further, in some cases, the default value for NDI may be used at thebase station as well, and when the base station schedules a HARQ ID fora first time the default NDI (e.g., NDI=0) may be used. In this case,the NDI value for the HARQ process in the one-shot report is known, nomatter whether the UE received the grant or not, which the base stationmay use to assist decoding (e.g., by providing a frozen bit to a Polardecoder).

FIG. 5 illustrates an example of a multiplexed feedback reports 500 thatsupports acknowledgment feedback techniques in shared radio frequencyspectrum in accordance with aspects of the present disclosure. In someexamples, multiplexed feedback reports 500 may implement aspects ofwireless communications system 100 or 200. In this example, a UE (e.g.,a UE 115 of FIG. 1 or 2) and a base station (e.g., a base station 105 ofFIG. 1 or 2) may establish multiple CCs for downlink transmissions,uplink transmissions, or both. In the example of FIG. 5, a first CC 505and a second CC 510 may be configured.

The base station may transmit downlink transmissions via the first CC505, which the UE may attempt to receive and decode. In this example,the UE may have eight HARQ processes configured, having HARQ IDs 1through 8. Further, scheduling information provided in DCI 540 forphysical downlink shared channel (PDSCH) transmissions 545 may includeDAI information (e.g., a counter DAI (cDAI) and a total DAI (tDAI)) thatmay be used (e.g., along with control channel monitoring occasioninformation) to determine a codebook for providing HARQ feedback 515.The DCI 540 may also provide a HARQ ID and NDI indicator for scheduledPDSCH transmissions 545.

In this example, the UE may not successfully transmit the HARQ feedback520, due to a failed LBT or interference from another transmitter, forexample. In this example, the base station may provide a DCI withone-shot HARQ trigger 535 to the UE to trigger a one-shot group HARQfeedback report 550. In this example, the UE may also be configured totransmit a regular HARQ feedback report, which may be multiplexed withthe one-shot HARQ feedback report in a multiplexed group HARQ feedbackreport 520. In this example, a first part 525 of the multiplexed groupHARQ feedback report 520 may include information that would normally betransmitted based on HARQ configuration of the UE, and may include asecond part 530 with the one-shot HARQ report. In this example, thefirst part 525 includes ACK/NACK information for downlink transmissionsaccording to configured HARQ reporting and timelines (e.g., regular type1 or type 2 HARQ codebooks based on cDAI, tDAI, control channelmonitoring occasions, etc.), and one-shot HARQ report in the second part530 may include feedback information for each configured HARQ ID (i.e.,HARQ IDs 1 through 8), which may include one or more repeated HARQindications for one or more HARQ IDs.

In some cases, the regular HARQ codebook and the one-shot HARQ reportcodebook may be multiplexed together (e.g., one-shot codebook is placedat the end of regular codebook). In some cases, the first part 525 andthe second part 530 may be concatenated before encoding the payload(i.e., payload concatenation) or after encoding (e.g., two codebooks areseparately encoded and then multiplexed). Further, in some cases, theregular codebook for part 1 525 may be CBG-based, or can be acrossmultiple CCs, and the one-shot codebook for part 2 530 can correspond toonly one CC (e.g., a requested CC either explicitly in the DCI, or basedon scheduling/scheduled CC as discussed with reference to FIG. 3) andcan be TB based. Note that in the example of FIG. 5, the feedbackinformation for HARQ IDs 2, 4, 6, 8 are reported in both the first part525 and the second part 530. Further, in this example, for HARQ ID 2,NACK is reported in the dynamic codebook for the first part 525 (sinceDCI is missed), and the feedback of the previous NDI is reported inone-shot codebook.

Alternatively, in some cases, when regular HARQ feedback is multiplexedtogether with one-shot HARQ feedback, the UE may drop the regular HARQfeedback codebook and only report the one-shot HARQ report. In somecases, the base station may configure this option when the HARQ IDsinvolved in the regular HARQ are fully covered by the one-shot HARQreport, such as if the one-shot HARQ triggers reporting of all HARQ IDsfor all CCs. In other cases, regular HARQ feedback and the one-shot HARQreport may be reported together but in separate resources instead ofwith payload concatenation. In such cases, additional resources may beconfigured for the one-shot HARQ report. For example, a PUCCH resourceindicator (PRI) may be linked to the regular HARQ feedback and to theone-shot HARQ report. In such cases, when the one-shot HARQ report istriggered in addition to the regular HARQ feedback, the PRI in the DCIcan point to a resource pair for regular HARQ feedback and one-shot HARQfeedback. Similarly, the feedback delay value K1 may point to a pair oftimelines for regular HARQ feedback and one-shot HARQ feedback, and theset of the resource pair and K1 pair can be pre-configured (e.g., viaRRC). In such cases, when both regular and one-shot HARQ feedback aretriggered, PRI and K1 point to the entry in the set with the resource/K1pair defined, and when only regular or one-shot HARQ feedback istriggered, PRI and K1 point to the entry in the set without resource/K1pair definition.

FIG. 6 illustrates an example of a feedback timing 600 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. In some examples,feedback timing 600 may implement aspects of wireless communicationssystem 100 or 200. In this example, a UE (e.g., a UE 115 of FIG. 1 or 2)and a base station (e.g., a base station 105 of FIG. 1 or 2) mayestablish communications (e.g., via one or multiple CCs) for downlinktransmissions, uplink transmissions, or both. In this example, UE maytransmit a first PUCCH 605, second PUCCH 610, and third PUCCH 615, andthe base station may transmit first PDSCH 625 transmissions for HARQ IDs1 through 4, and second PDSCH 630 transmissions for HARQ IDs 5 and 6.

For regular HARQ transmissions, a value of K1 may be used to indicatethe time between PDSCH-to-HARQ in terms of number of slots, which inthis example is indicated as feedback timeline 620. Thus, in this caseHARQ IDs 1 through 4 may have feedback provided in the second PUCCH 610transmission, and HARQ IDs 5 and 6 may have feedback provided in thethird PUCCH 615 transmission. For one-shot HARQ reports, the UE reportsfeedback for all HARQ IDs, and using the rules for regular HARQtransmissions may introduce ambiguity for what is the last PDSCH thatthe UE has to complete the decoding and reporting the HARQ feedback. Forexample, there may be 8 configured HARQ IDs, and HARQ IDs 1-6 arescheduled back to back, as illustrated in FIG. 6, and one-shot feedbackis only requested in the DCIs scheduling PDSCH with HARQ IDs 2, 3, 4. Atthe time of scheduling PDSCH for HARQ ID 1, the base station has notfinished decoding the previous PUCCH, so does not know if a one-shotHARQ feedback is needed. In such a case, one-shot feedback may berequested in the next 3 DCIs (e.g., in response to not being able todecode PUCCH1). However, with the last two DCIs having a K1 pointing toanother PUCCH there is no need to request one-shot feedback for thatPUCCH yet.

In the example of FIG. 6, the last PDSCH for which HARQ results isreported in one-shot HARQ feedback is the PDSCH that is scheduled by thelast DCI among all the DCIs in which one-shot feedback is requested andpoints to the same slot for PUCCH transmission. For example, forone-shot feedback in the second PUCCH 610, the last PDSCH is associatedwith HARQ ID 4. For HARQ IDs 5 and 6, the HARQ feedback for the previousPDSCH is reported (i.e., the UE does not include feedback of the lasttwo PDSCHs in the one-shot HARQ feedback in the second PUCCH 610). Inthis example, it is assumed that the request is carried in a UE-specificDCI carrying a PDSCH assignment. In other cases (DCI requesting one-shotfeedback does not carry PDSCH assignment), the last PDSCH for which HARQresults is reported in one-shot HARQ-Ack feedback is either the lastPDSCH that is scheduled or received before the last DCI among all theDCIs in which one-shot feedback is requested and points to the same slotfor HARQ-Ack transmission.

FIG. 7 illustrates an example of a feedback timing 700 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. In some examples,feedback timing 700 may implement aspects of wireless communicationssystem 100 or 200. In this example, a UE (e.g., a UE 115 of FIG. 1 or 2)and a base station (e.g., a base station 105 of FIG. 1 or 2) mayestablish communications (e.g., via one or multiple CCs) for downlinktransmissions, uplink transmissions, or both. In this example, UE maytransmit a first PUCCH 705, second PUCCH 710, and third PUCCH 715, andthe base station may transmit first PDSCH 725 transmissions for HARQ IDs1 through 4, and second PDSCH 730 transmissions for HARQ IDs 5 and 6.

In this example, when a one-shot HARQ request is received, the UE mayreport the latest HARQ result only if a timeline condition N1 issatisfied, which may be a function of UE processing capability (e.g.,the value of N1 based on UE capability indication (i.e., capability 1 orcapability 2)). In this case, the UE counts back N1 symbols from thefirst symbol of the second PUCCH 710, and HARQ feedback for any PDSCHbefore that should be reported in one-shot feedback. In the example ofFIG. 7, the UE would report HARQ IDs 1 through 5 in the one-shot HARQreport that is transmitted in the second PUCCH 710. In cases where HARQfeedback is carried on PUSCH, the first symbol of PUSCH is consideredfor the N1 determination. In the example of FIG. 7, the downlinktransmission associated with HARQ ID 5 is transmitted in both theone-shot HARQ report, as well as in the regular HARQ report provided inthe third PUCCH transmission 715. In this example, HARQ ID 6, HARQinformation of the previous PDSCH (e.g. received before PUCCH1) isreported in the one-shot feedback. In some cases, the symbol to use forthe N1 timeline determination may be an actual PUCCH/PUSCH transmissionafter uplink control information (UCI) multiplexing is considered.Alternatively, the PUCCH that the HARQ information was originallyintended to be transmitted on is considered before UCI multiplexing ifpresent (i.e., the PUCCH resource indicated by PRI field in the last DCIamong all the DCIs that have a value of K1 indicating a same slot forPUCCH transmission). In further cases, the two first symbols accordingto the two above alternatives are determined, and the earliest symbolfrom the two is considered for the N1 determination.

FIG. 8 shows a block diagram 800 of a device 805 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The device 805 may bean example of aspects of a UE 115 as described herein. The device 805may include a receiver 810, a communications manager 815, and atransmitter 820. The device 805 may also include a processor. Each ofthese components may be in communication with one another (e.g., via oneor more buses).

The receiver 810 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related toacknowledgment feedback techniques in shared radio frequency spectrum,etc.). Information may be passed on to other components of the device805. The receiver 810 may be an example of aspects of the transceiver1120 described with reference to FIG. 11. The receiver 810 may utilize asingle antenna or a set of antennas.

The communications manager 815 may determine HARQ feedback for a set ofdownlink transmissions from a base station, receive, from the basestation, downlink control information that indicates the UE is toprovide a feedback report for a subset of downlink transmissions, wherethe subset of downlink transmissions is less than the set of downlinktransmissions, and transmit, to the base station, the feedback reportincluding the HARQ feedback for the subset of downlink transmissions.

The communications manager 815 may also determine HARQ feedback for aset of downlink transmissions from a base station, where each of the setof downlink transmissions has an associated data indicator thatindicates whether the downlink transmission includes an initialtransmission of a transport block or a retransmission of a previouslytransmitted transport block, receive, from the base station, downlinkcontrol information that indicates the UE is to provide a feedbackreport for at least a subset of the downlink transmissions, identify,for each downlink transmission of at least the subset of downlinktransmissions, associated HARQ feedback based on one or more of athree-state indication of HARQ feedback, a default data indicator, orany combinations thereof, and transmit, to the base station, thefeedback report including the HARQ feedback for at least the subset ofthe downlink transmissions.

The communications manager 815 may also receive, from a base station, aresource allocation for a first subset of downlink transmissions,receive, from the base station, downlink control information thatindicates the UE is to provide a second feedback report for a secondsubset of downlink transmissions, where the second subset of downlinktransmissions includes one or more different downlink transmissions thanthe first subset of downlink transmissions, determine that HARQ feedbackfor one or more of the first subset of downlink transmissions is to beprovided in a first feedback report, determine a first subset of HARQfeedback for the first subset of downlink transmissions and a secondsubset of HARQ feedback for the second subset of downlink transmissions,and transmit, to the base station, the first subset of HARQ feedbackmultiplexed with the second subset of HARQ feedback in one or morefeedback reports.

The communications manager 815 may also receive, from a base station,downlink control information that indicates the UE is to provide afeedback report for a set of downlink transmissions, determine HARQfeedback for the set of downlink transmissions from the base station,format the feedback report for transmission to the base station, where alast downlink transmission of the set of downlink transmissions to beincluded in the feedback report is determined based on a timing thedownlink control information that schedules the set of downlinktransmissions, a latest downlink transmission that meets a feedbacktimeline condition, or any combinations thereof, and transmit, to thebase station, the feedback report including the HARQ feedback for theset of the downlink transmissions. The communications manager 815 may bean example of aspects of the communications manager 1110 describedherein.

The communications manager 815, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 815, or itssub-components may be executed by a general-purpose processor, a DSP, anapplication-specific integrated circuit (ASIC), a FPGA or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described in the present disclosure.

The communications manager 815, or its sub-components, may be physicallylocated at various positions, including being distributed such thatportions of functions are implemented at different physical locations byone or more physical components. In some examples, the communicationsmanager 815, or its sub-components, may be a separate and distinctcomponent in accordance with various aspects of the present disclosure.In some examples, the communications manager 815, or its sub-components,may be combined with one or more other hardware components, includingbut not limited to an input/output (I/O) component, a transceiver, anetwork server, another computing device, one or more other componentsdescribed in the present disclosure, or a combination thereof inaccordance with various aspects of the present disclosure.

The transmitter 820 may transmit signals generated by other componentsof the device 805. In some examples, the transmitter 820 may becollocated with a receiver 810 in a transceiver module. For example, thetransmitter 820 may be an example of aspects of the transceiver 1120described with reference to FIG. 11. The transmitter 820 may utilize asingle antenna or a set of antennas.

FIG. 9 shows a block diagram 900 of a device 905 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The device 905 may bean example of aspects of a device 805, or a UE 115 as described herein.The device 905 may include a receiver 910, a communications manager 915,and a transmitter 940. The device 905 may also include a processor. Eachof these components may be in communication with one another (e.g., viaone or more buses).

The receiver 910 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related toacknowledgment feedback techniques in shared radio frequency spectrum,etc.). Information may be passed on to other components of the device905. The receiver 910 may be an example of aspects of the transceiver1120 described with reference to FIG. 11. The receiver 910 may utilize asingle antenna or a set of antennas.

The communications manager 915 may be an example of aspects of thecommunications manager 815 as described herein. The communicationsmanager 915 may include a HARQ feedback manager 920, a DCI manager 925,an one-shot report manager 930, and a codebook manager 935. Thecommunications manager 915 may be an example of aspects of thecommunications manager 1110 described herein.

The HARQ feedback manager 920 may determine HARQ feedback for a set ofdownlink transmissions from a base station. The DCI manager 925 mayreceive, from the base station, downlink control information thatindicates the UE is to provide a feedback report for a subset ofdownlink transmissions, where the subset of downlink transmissions isless than the set of downlink transmissions. The one-shot report manager930 may transmit, to the base station, the feedback report including theHARQ feedback for the subset of downlink transmissions.

In some cases, the HARQ feedback manager 920 may determine HARQ feedbackfor a set of downlink transmissions from a base station, where each ofthe set of downlink transmissions has an associated data indicator thatindicates whether the downlink transmission includes an initialtransmission of a transport block or a retransmission of a previouslytransmitted transport block. The DCI manager 925 may receive, from thebase station, downlink control information that indicates the UE is toprovide a feedback report for at least a subset of the downlinktransmissions. The codebook manager 935 may identify, for each downlinktransmission of at least the subset of downlink transmissions,associated HARQ feedback based on one or more of a three-stateindication of HARQ feedback, a default data indicator, or anycombinations thereof. The one-shot report manager 930 may transmit, tothe base station, the feedback report including the HARQ feedback for atleast the subset of the downlink transmissions.

In some cases, the DCI manager 925 may receive, from a base station, aresource allocation for a first subset of downlink transmissions andreceive, from the base station, downlink control information thatindicates the UE is to provide a second feedback report for a secondsubset of downlink transmissions, where the second subset of downlinktransmissions includes one or more different downlink transmissions thanthe first subset of downlink transmissions. The HARQ feedback manager920 may determine that HARQ feedback for one or more of the first subsetof downlink transmissions is to be provided in a first feedback reportand determine a first subset of HARQ feedback for the first subset ofdownlink transmissions and a second subset of HARQ feedback for thesecond subset of downlink transmissions. The one-shot report manager 930may transmit, to the base station, the first subset of HARQ feedbackmultiplexed with the second subset of HARQ feedback in one or morefeedback reports.

In some cases, the DCI manager 925 may receive, from a base station,downlink control information that indicates the UE is to provide afeedback report for a set of downlink transmissions. The HARQ feedbackmanager 920 may determine HARQ feedback for the set of downlinktransmissions from the base station. The one-shot report manager 930 mayformat the feedback report for transmission to the base station, where alast downlink transmission of the set of downlink transmissions to beincluded in the feedback report is determined based on a timing thedownlink control information that schedules the set of downlinktransmissions, a latest downlink transmission that meets a feedbacktimeline condition, or any combinations thereof and transmit, to thebase station, the feedback report including the HARQ feedback for theset of the downlink transmissions.

The transmitter 940 may transmit signals generated by other componentsof the device 905. In some examples, the transmitter 940 may becollocated with a receiver 910 in a transceiver module. For example, thetransmitter 940 may be an example of aspects of the transceiver 1120described with reference to FIG. 11. The transmitter 940 may utilize asingle antenna or a set of antennas.

FIG. 10 shows a block diagram 1000 of a communications manager 1005 thatsupports acknowledgment feedback techniques in shared radio frequencyspectrum in accordance with aspects of the present disclosure. Thecommunications manager 1005 may be an example of aspects of acommunications manager 815, a communications manager 915, or acommunications manager 1110 described herein. The communications manager1005 may include a HARQ feedback manager 1010, a DCI manager 1015, anone-shot report manager 1020, a codebook manager 1025, a NDI manager1030, a multiplexing component 1035, an encoder 1040, and a feedbackresource manager 1045. Each of these modules may communicate, directlyor indirectly, with one another (e.g., via one or more buses).

The HARQ feedback manager 1010 may determine HARQ feedback for a set ofdownlink transmissions from a base station. In some examples, the HARQfeedback manager 1010 may determine HARQ feedback for a set of downlinktransmissions from a base station, where each of the set of downlinktransmissions has an associated data indicator that indicates whetherthe downlink transmission includes an initial transmission of atransport block or a retransmission of a previously transmittedtransport block. In some examples, the HARQ feedback manager 1010 maydetermine that HARQ feedback for one or more of the first subset ofdownlink transmissions is to be provided in a first feedback report. Insome examples, the HARQ feedback manager 1010 may determine a firstsubset of HARQ feedback for the first subset of downlink transmissionsand a second subset of HARQ feedback for the second subset of downlinktransmissions.

In some examples, the HARQ feedback manager 1010 may determine HARQfeedback for the set of downlink transmissions from the base station. Insome examples, the HARQ feedback manager 1010 may transmit the firstsubset of HARQ feedback using a first set of uplink resources. In someexamples, the HARQ feedback manager 1010 may transmit the second subsetof HARQ feedback using a second set of uplink resources.

In some cases, the HARQ feedback includes one or more of acknowledgment(ACK) indications, negative acknowledgment (NACK) indications, a newdata indicator (NDI), or combinations thereof, that are each associatedwith a corresponding downlink transmission of the set of downlinktransmissions.

The DCI manager 1015 may receive, from the base station, downlinkcontrol information that indicates the UE is to provide a feedbackreport for a subset of downlink transmissions, where the subset ofdownlink transmissions is less than the set of downlink transmissions.In some examples, the DCI manager 1015 may receive, from the basestation, downlink control information that indicates the UE is toprovide a feedback report for at least a subset of the downlinktransmissions. In some examples, the DCI manager 1015 may receive, froma base station, a resource allocation for a first subset of downlinktransmissions. In some examples, the DCI manager 1015 may receive, fromthe base station, downlink control information that indicates the UE isto provide a second feedback report for a second subset of downlinktransmissions, where the second subset of downlink transmissionsincludes one or more different downlink transmissions than the firstsubset of downlink transmissions. In some examples, the DCI manager 1015may receive, from a base station, downlink control information thatindicates the UE is to provide a feedback report for a set of downlinktransmissions.

In some examples, the DCI manager 1015 may receive a set of informationfields in the downlink control information. In some examples, the DCImanager 1015 may determine, based on a first information field of theset of information fields, the subset of downlink transmissions to beincluded with the feedback report.

In some cases, the set of downlink transmissions include a set ofdownlink transmissions that are associated with one or more of a set oftransport blocks, a set of component carriers, a set of feedback processidentifications, a set of code block groups, or any combinationsthereof. In some cases, the first set of uplink resources and second setof uplink resources are indicated in the downlink control information.

The one-shot report manager 1020 may transmit, to the base station, thefeedback report including the HARQ feedback for the subset of downlinktransmissions. In some examples, the one-shot report manager 1020 maytransmit, to the base station, the first subset of HARQ feedbackmultiplexed with the second subset of HARQ feedback in one or morefeedback reports. In some examples, the one-shot report manager 1020 mayformat the feedback report for transmission to the base station, where alast downlink transmission of the set of downlink transmissions to beincluded in the feedback report is determined based on a timing thedownlink control information that schedules the set of downlinktransmissions, a latest downlink transmission that meets a feedbacktimeline condition, or any combinations thereof.

In some examples, the one-shot report manager 1020 may format first andsecond codebook entries into first and second feedback reports. In someexamples, the one-shot report manager 1020 may transmit the feedbackreports to the base station.

In some examples, the one-shot report manager 1020 may determine thelast downlink transmission as a latest downlink transmission thatscheduled in the downlink control information. In some examples, theone-shot report manager 1020 may determine the last downlinktransmission as a latest downlink transmission that scheduled in one oftwo or more different downlink control information transmissions inwhich the feedback report is requested and that indicates a same set ofuplink resources for transmitting the feedback report. In some examples,the one-shot report manager 1020 may determine the last downlinktransmission as a latest downlink transmission that is received prior toreceiving the downlink control information. In some examples, theone-shot report manager 1020 may determine the last downlinktransmission as a latest downlink transmission that satisfies thefeedback timeline condition, and where the feedback timeline conditionindicates a minimum time duration between receiving a downlinktransmission and transmitting associated HARQ feedback.

In some cases, the first information field provides an explicitindication of the subset of downlink transmissions to be included withthe feedback report. In some cases, the explicit indication specifiesone or more component carriers, transport blocks, feedback processidentifications, code blocks, or any combinations thereof to be includedwith the feedback report. In some cases, the first information fieldprovides an implicit indication of the subset of downlink transmissionsto be included with the feedback report. In some cases, the implicitindication is based on one or more component carriers (CCs) scheduled inthe downlink control information, a CC used to transmit the downlinkcontrol information, or any combinations thereof. In some cases, thefirst field is a downlink assignment indicator field that is reused toindicate the subset of downlink transmissions to be included with thefeedback report.

In some cases, the first subset of HARQ feedback includes HARQ feedbackfor at least a first downlink transmission, and the second subset ofHARQ feedback also includes the HARQ feedback for at least the firstdownlink transmission.

In some cases, a first symbol of a set of uplink resources fortransmitting the feedback report is selected for determining the minimumtime duration, and where the first symbol of the set of uplink resourcesis determined based on one or more of uplink control informationmultiplexing of the feedback report with other uplink controlinformation, or an uplink control channel resource indicator providedwith the downlink control information.

The codebook manager 1025 may identify, for each downlink transmissionof at least the subset of downlink transmissions, associated HARQfeedback based on one or more of a three-state indication of HARQfeedback, a default data indicator, or any combinations thereof. In someexamples, the codebook manager 1025 may identify a codebook entryassociated with the acknowledgment feedback for a set of feedbackprocess identifications to be reported in the feedback report.

In some examples, the codebook manager 1025 may identify a firstcodebook entry associated with the first subset of HARQ feedback, wherethe first codebook entry is mapped to the first subset of HARQ feedbackand one or more parameters associated with the first subset of downlinktransmissions. In some examples, the codebook manager 1025 may identifya second codebook entry associated with the second subset ofacknowledgment feedback, where the second codebook entry is mapped tothe second subset of HARQ feedback and one or more different parametersthan the first codebook entry. In some examples, the codebook manager1025 may identify a second codebook entry associated with the secondsubset of HARQ feedback based on the multiplexed set of HARQ feedback.

The NDI manager 1030 may manage NDI information associated with HARQIDs. In some cases, a default data indication is reported for a firstfeedback process identification for which the UE has not receivedscheduling information that indicates the first feedback processidentification is to be used to indicate feedback for one of the subsetof the downlink transmissions.

The multiplexing component 1035 may concatenate the second feedbackreport with the first feedback report. In some examples, themultiplexing component 1035 may multiplex the first subset of HARQfeedback and the second subset of HARQ feedback to generate amultiplexed set of HARQ feedback. The encoder 1040 may encode a payloadof each of the first feedback report and the second feedback report,where the encoding is performed before or after the concatenating.

The feedback resource manager 1045 may identify uplink resources forHARQ transmissions. In some cases, the downlink control informationprovides an uplink control channel resource indicator that is mapped tothe first set of uplink resources and the second set of uplinkresources. In some cases, a timeline for transmissions using the firstset of uplink resources and second set of uplink resources is indicatedby a feedback timing indicator that is mapped to time domain resourcesof the first set of uplink resources and second set of uplink resources.

FIG. 11 shows a diagram of a system 1100 including a device 1105 thatsupports acknowledgment feedback techniques in shared radio frequencyspectrum in accordance with aspects of the present disclosure. Thedevice 1105 may be an example of or include the components of device805, device 905, or a UE 115 as described herein. The device 1105 mayinclude components for bi-directional voice and data communicationsincluding components for transmitting and receiving communications,including a communications manager 1110, an I/O controller 1115, atransceiver 1120, an antenna 1125, memory 1130, and a processor 1140.These components may be in electronic communication via one or morebuses (e.g., bus 1145).

The communications manager 1110 may determine HARQ feedback for a set ofdownlink transmissions from a base station, receive, from the basestation, downlink control information that indicates the UE is toprovide a feedback report for a subset of downlink transmissions, wherethe subset of downlink transmissions is less than the set of downlinktransmissions, and transmit, to the base station, the feedback reportincluding the HARQ feedback for the subset of downlink transmissions.

The communications manager 1110 may also determine HARQ feedback for aset of downlink transmissions from a base station, where each of the setof downlink transmissions has an associated data indicator thatindicates whether the downlink transmission includes an initialtransmission of a transport block or a retransmission of a previouslytransmitted transport block, receive, from the base station, downlinkcontrol information that indicates the UE is to provide a feedbackreport for at least a subset of the downlink transmissions, identify,for each downlink transmission of at least the subset of downlinktransmissions, associated HARQ feedback based on one or more of athree-state indication of HARQ feedback, a default data indicator, orany combinations thereof, and transmit, to the base station, thefeedback report including the HARQ feedback for at least the subset ofthe downlink transmissions.

The communications manager 1110 may also receive, from a base station, aresource allocation for a first subset of downlink transmissions,receive, from the base station, downlink control information thatindicates the UE is to provide a second feedback report for a secondsubset of downlink transmissions, where the second subset of downlinktransmissions includes one or more different downlink transmissions thanthe first subset of downlink transmissions, determine that HARQ feedbackfor one or more of the first subset of downlink transmissions is to beprovided in a first feedback report, determine a first subset of HARQfeedback for the first subset of downlink transmissions and a secondsubset of HARQ feedback for the second subset of downlink transmissions,and transmit, to the base station, the first subset of HARQ feedbackmultiplexed with the second subset of HARQ feedback in one or morefeedback reports.

The communications manager 1110 may also receive, from a base station,downlink control information that indicates the UE is to provide afeedback report for a set of downlink transmissions, determine HARQfeedback for the set of downlink transmissions from the base station,format the feedback report for transmission to the base station, where alast downlink transmission of the set of downlink transmissions to beincluded in the feedback report is determined based on a timing thedownlink control information that schedules the set of downlinktransmissions, a latest downlink transmission that meets a feedbacktimeline condition, or any combinations thereof, and transmit, to thebase station, the feedback report including the HARQ feedback for theset of the downlink transmissions.

The I/O controller 1115 may manage input and output signals for thedevice 1105. The I/O controller 1115 may also manage peripherals notintegrated into the device 1105. In some cases, the I/O controller 1115may represent a physical connection or port to an external peripheral.In some cases, the I/O controller 1115 may utilize an operating systemsuch as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, oranother known operating system. In other cases, the I/O controller 1115may represent or interact with a modem, a keyboard, a mouse, atouchscreen, or a similar device. In some cases, the I/O controller 1115may be implemented as part of a processor. In some cases, a user mayinteract with the device 1105 via the I/O controller 1115 or viahardware components controlled by the I/O controller 1115.

The transceiver 1120 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1120 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1120 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1125.However, in some cases the device may have more than one antenna 1125,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 1130 may include RAM and ROM. The memory 1130 may storecomputer-readable, computer-executable code 1135 including instructionsthat, when executed, cause the processor to perform various functionsdescribed herein. In some cases, the memory 1130 may contain, amongother things, a BIOS which may control basic hardware or softwareoperation such as the interaction with peripheral components or devices.

The processor 1140 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1140 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into the processor 1140. The processor 1140 may beconfigured to execute computer-readable instructions stored in a memory(e.g., the memory 1130) to cause the device 1105 to perform variousfunctions (e.g., functions or tasks supporting acknowledgment feedbacktechniques in shared radio frequency spectrum).

The code 1135 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 1135 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 1135 may not be directly executable by theprocessor 1140 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 12 shows a block diagram 1200 of a device 1205 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The device 1205 maybe an example of aspects of a base station 105 as described herein. Thedevice 1205 may include a receiver 1210, a communications manager 1215,and a transmitter 1220. The device 1205 may also include a processor.Each of these components may be in communication with one another (e.g.,via one or more buses).

The receiver 1210 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related toacknowledgment feedback techniques in shared radio frequency spectrum,etc.). Information may be passed on to other components of the device1205. The receiver 1210 may be an example of aspects of the transceiver1520 described with reference to FIG. 15. The receiver 1210 may utilizea single antenna or a set of antennas.

The communications manager 1215 may transmit a set of downlinktransmissions to a UE, the set of downlink transmissions having one ormore corresponding sets of uplink resources for transmission of HARQfeedback from the UE, determine, based on monitoring the one or moresets of uplink resources, that HARQ feedback from the UE is missing forone or more downlink transmissions of the set of downlink transmissions,and transmit, to the UE, downlink control information that indicates theUE is to provide a feedback report for a subset of downlinktransmissions, where the subset of downlink transmissions is less thanthe set of downlink transmissions.

The communications manager 1215 may also configure a UE for reportingHARQ feedback that indicates successful or unsuccessful reception of oneor more downlink transmissions at the UE, where each downlinktransmission has an associated data indicator that indicates whether thedownlink transmission includes an initial transmission of a transportblock or a retransmission of a previously transmitted transport block,and where the HARQ feedback indicates one or more of a default dataindication, a three-state indication of feedback based on anacknowledgment (ACK) and transport block indication or a negativeacknowledgment (NACK) indication, or combinations thereof, transmit aset of downlink transmissions to the UE, the set of downlinktransmissions having one or more corresponding sets of uplink resourcesfor transmission of HARQ feedback from the UE, determine, based onmonitoring the one or more sets of uplink resources, that HARQ feedbackfrom the UE is missing for one or more downlink transmissions of the setof downlink transmissions, transmit, to the UE, downlink controlinformation that indicates the UE is to provide a feedback report for atleast the one or more downlink transmissions, and receive, from the UE,the feedback report that indicates, for each of the one or more downlinktransmissions, one or more of the three-state indication of feedback,the default data indication, or any combinations thereof.

The communications manager 1215 may also transmit a first subset ofdownlink transmissions to a UE, the first subset of downlinktransmissions having one or more corresponding sets of uplink resourcesfor transmission of HARQ feedback from the UE, determine, based onmonitoring the one or more sets of uplink resources, that HARQ feedbackfrom the UE is missing for one or more downlink transmissions of thefirst subset of downlink transmissions, transmit, to the UE, downlinkcontrol information that includes a resource allocation for secondsubset of downlink transmissions and that indicates that the UE is toprovide a first feedback report for the first subset of downlinktransmissions, and where the second subset of downlink transmissionshave an associated second feedback report, and receive, from the UE, thefirst feedback report multiplexed with the second feedback report in oneor more uplink control information transmissions.

The communications manager 1215 may also transmit, to a UE, downlinkcontrol information that indicates the UE is to provide a feedbackreport for a set of downlink transmissions, receive the feedback reportfrom the UE, where a last downlink transmission of the set of downlinktransmissions that is included in the feedback report is determinedbased on a timing the downlink control information that schedules theset of downlink transmissions, a latest downlink transmission that meetsa feedback timeline condition, or any combinations thereof, anddetermine HARQ feedback based on the feedback report. The communicationsmanager 1215 may be an example of aspects of the communications manager1510 described herein.

The communications manager 1215, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 1215, or itssub-components may be executed by a general-purpose processor, a DSP, anapplication-specific integrated circuit (ASIC), a FPGA or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described in the present disclosure.

The communications manager 1215, or its sub-components, may bephysically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations by one or more physical components. In some examples, thecommunications manager 1215, or its sub-components, may be a separateand distinct component in accordance with various aspects of the presentdisclosure. In some examples, the communications manager 1215, or itssub-components, may be combined with one or more other hardwarecomponents, including but not limited to an input/output (I/O)component, a transceiver, a network server, another computing device,one or more other components described in the present disclosure, or acombination thereof in accordance with various aspects of the presentdisclosure.

The transmitter 1220 may transmit signals generated by other componentsof the device 1205. In some examples, the transmitter 1220 may becollocated with a receiver 1210 in a transceiver module. For example,the transmitter 1220 may be an example of aspects of the transceiver1520 described with reference to FIG. 15. The transmitter 1220 mayutilize a single antenna or a set of antennas.

FIG. 13 shows a block diagram 1300 of a device 1305 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The device 1305 maybe an example of aspects of a device 1205, or a base station 105 asdescribed herein. The device 1305 may include a receiver 1310, acommunications manager 1315, and a transmitter 1345. The device 1305 mayalso include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses).

The receiver 1310 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related toacknowledgment feedback techniques in shared radio frequency spectrum,etc.). Information may be passed on to other components of the device1305. The receiver 1310 may be an example of aspects of the transceiver1520 described with reference to FIG. 15. The receiver 1310 may utilizea single antenna or a set of antennas.

The communications manager 1315 may be an example of aspects of thecommunications manager 1215 as described herein. The communicationsmanager 1315 may include a PDSCH manager 1320, a HARQ feedback manager1325, a DCI manager 1330, a configuration manager 1335, and an one-shotreport manager 1340. The communications manager 1315 may be an exampleof aspects of the communications manager 1510 described herein.

In some cases, the PDSCH manager 1320 may transmit a set of downlinktransmissions to a UE, the set of downlink transmissions having one ormore corresponding sets of uplink resources for transmission of HARQfeedback from the UE. The HARQ feedback manager 1325 may determine,based on monitoring the one or more sets of uplink resources, that HARQfeedback from the UE is missing for one or more downlink transmissionsof the set of downlink transmissions. The DCI manager 1330 may transmit,to the UE, downlink control information that indicates the UE is toprovide a feedback report for a subset of downlink transmissions, wherethe subset of downlink transmissions is less than the set of downlinktransmissions.

In some cases, the configuration manager 1335 may configure a UE forreporting HARQ feedback that indicates successful or unsuccessfulreception of one or more downlink transmissions at the UE, where eachdownlink transmission has an associated data indicator that indicateswhether the downlink transmission includes an initial transmission of atransport block or a retransmission of a previously transmittedtransport block, and where the HARQ feedback indicates one or more of adefault data indication, a three-state indication of feedback based onan acknowledgment (ACK) and transport block indication or a negativeacknowledgment (NACK) indication, or combinations thereof. The PDSCHmanager 1320 may transmit a set of downlink transmissions to the UE, theset of downlink transmissions having one or more corresponding sets ofuplink resources for transmission of HARQ feedback from the UE. The HARQfeedback manager 1325 may determine, based on monitoring the one or moresets of uplink resources, that HARQ feedback from the UE is missing forone or more downlink transmissions of the set of downlink transmissions.The DCI manager 1330 may transmit, to the UE, downlink controlinformation that indicates the UE is to provide a feedback report for atleast the one or more downlink transmissions. The one-shot reportmanager 1340 may receive, from the UE, the feedback report thatindicates, for each of the one or more downlink transmissions, one ormore of the three-state indication of feedback, the default dataindication, or any combinations thereof.

In some cases, the PDSCH manager 1320 may transmit a first subset ofdownlink transmissions to a UE, the first subset of downlinktransmissions having one or more corresponding sets of uplink resourcesfor transmission of HARQ feedback from the UE. The HARQ feedback manager1325 may determine, based on monitoring the one or more sets of uplinkresources, that HARQ feedback from the UE is missing for one or moredownlink transmissions of the first subset of downlink transmissions.The DCI manager 1330 may transmit, to the UE, downlink controlinformation that includes a resource allocation for second subset ofdownlink transmissions and that indicates that the UE is to provide afirst feedback report for the first subset of downlink transmissions,and where the second subset of downlink transmissions have an associatedsecond feedback report. The one-shot report manager 1340 may receive,from the UE, the first feedback report multiplexed with the secondfeedback report in one or more uplink control information transmissions.

In some cases, the DCI manager 1330 may transmit, to a UE, downlinkcontrol information that indicates the UE is to provide a feedbackreport for a set of downlink transmissions. The one-shot report manager1340 may receive the feedback report from the UE, where a last downlinktransmission of the set of downlink transmissions that is included inthe feedback report is determined based on a timing the downlink controlinformation that schedules the set of downlink transmissions, a latestdownlink transmission that meets a feedback timeline condition, or anycombinations thereof. The HARQ feedback manager 1325 may determine HARQfeedback based on the feedback report.

The transmitter 1345 may transmit signals generated by other componentsof the device 1305. In some examples, the transmitter 1345 may becollocated with a receiver 1310 in a transceiver module. For example,the transmitter 1345 may be an example of aspects of the transceiver1520 described with reference to FIG. 15. The transmitter 1345 mayutilize a single antenna or a set of antennas.

FIG. 14 shows a block diagram 1400 of a communications manager 1405 thatsupports acknowledgment feedback techniques in shared radio frequencyspectrum in accordance with aspects of the present disclosure. Thecommunications manager 1405 may be an example of aspects of acommunications manager 1215, a communications manager 1315, or acommunications manager 1510 described herein. The communications manager1405 may include a PDSCH manager 1410, a HARQ feedback manager 1415, aDCI manager 1420, a configuration manager 1425, an one-shot reportmanager 1430, a codebook manager 1435, a NDI manager 1440, amultiplexing component 1445, a decoder 1450, and a feedback resourcemanager 1455. Each of these modules may communicate, directly orindirectly, with one another (e.g., via one or more buses).

The PDSCH manager 1410 may transmit a set of downlink transmissions to aUE, the set of downlink transmissions having one or more correspondingsets of uplink resources for transmission of HARQ feedback from the UE.

In some examples, the PDSCH manager 1410 may transmit a set of downlinktransmissions to the UE, the set of downlink transmissions having one ormore corresponding sets of uplink resources for transmission of HARQfeedback from the UE.

In some examples, the PDSCH manager 1410 may transmit a first subset ofdownlink transmissions to a UE, the first subset of downlinktransmissions having one or more corresponding sets of uplink resourcesfor transmission of HARQ feedback from the UE.

The HARQ feedback manager 1415 may determine, based on monitoring theone or more sets of uplink resources, that HARQ feedback from the UE ismissing for one or more downlink transmissions of the set of downlinktransmissions.

In some examples, the HARQ feedback manager 1415 may determine, based onmonitoring the one or more sets of uplink resources, that HARQ feedbackfrom the UE is missing for one or more downlink transmissions of the setof downlink transmissions.

In some examples, the HARQ feedback manager 1415 may determine, based onmonitoring the one or more sets of uplink resources, that HARQ feedbackfrom the UE is missing for one or more downlink transmissions of thefirst subset of downlink transmissions.

In some examples, the HARQ feedback manager 1415 may determine HARQfeedback based on the feedback report. In some examples, the HARQfeedback manager 1415 may receive a multiplexed set of HARQ feedback. Insome examples, the HARQ feedback manager 1415 may determine the HARQfeedback from the UE for each of the first feedback report and thesecond feedback report based on a mapping between the codebooks and HARQfeedback.

In some cases, the HARQ feedback includes one or more of acknowledgment(ACK) indications, negative acknowledgment (NACK) indications, a newdata indicator (NDI), or combinations thereof, that are each associatedwith a corresponding downlink transmission of the set of downlinktransmissions. In some cases, the first feedback report includes HARQfeedback for at least a first downlink transmission, and the secondfeedback report also includes the HARQ feedback for at least the firstdownlink transmission.

The DCI manager 1420 may transmit, to the UE, downlink controlinformation that indicates the UE is to provide a feedback report for atleast a subset of downlink transmissions, where the subset of downlinktransmissions is less than the set of downlink transmissions.

In some examples, the DCI manager 1420 may transmit, to the UE, downlinkcontrol information that includes a resource allocation for secondsubset of downlink transmissions and that indicates that the UE is toprovide a first feedback report for the first subset of downlinktransmissions, and where the second subset of downlink transmissionshave an associated second feedback report.

In some examples, the DCI manager 1420 may transmit a set of informationfields in the downlink control information, where a first informationfield of the set of information fields indicates the subset of downlinktransmissions to be included with the feedback report.

In some cases, the subset of downlink transmissions include one or moredownlink transmissions that are associated with one a transport block ofa set of transport blocks, a component carrier of a set of componentcarriers, a feedback process identification of a set of feedback processidentifications, a code block of a set of code blocks, or anycombinations thereof.

In some cases, the first information field provides an explicitindication of the subset of downlink transmissions to be included withthe feedback report. In some cases, the explicit indication specifiesone or more component carriers, transport blocks, feedback processidentifications, code blocks, or any combinations thereof to be includedwith the feedback report. In some cases, the first information fieldprovides an implicit indication of the subset of downlink transmissionsto be included with the feedback report. In some cases, the implicitindication is based on one or more component carriers (CCs) scheduled inthe downlink control information, a CC used to transmit the downlinkcontrol information, or any combinations thereof.

In some cases, the first field is a downlink assignment indicator fieldthat is reused to indicate the subset of downlink transmissions to beincluded with the feedback report. In some cases, the first set ofuplink resources and the second set of uplink resources are indicated inthe downlink control information. In some cases, the downlink controlinformation provides an uplink control channel resource indicator thatis mapped to the first set of uplink resources and the second set ofuplink resources.

The configuration manager 1425 may configure a UE for reporting HARQfeedback that indicates successful or unsuccessful reception of one ormore downlink transmissions at the UE, where each downlink transmissionhas an associated data indicator that indicates whether the downlinktransmission includes an initial transmission of a transport block or aretransmission of a previously transmitted transport block, and wherethe HARQ feedback indicates one or more of a default data indication, athree-state indication of feedback based on an acknowledgment (ACK) andtransport block indication or a negative acknowledgment (NACK)indication, or combinations thereof.

The one-shot report manager 1430 may receive, from the UE, the feedbackreport that indicates, for each of the one or more downlinktransmissions, one or more of the three-state indication of feedback,the default data indication, or any combinations thereof.

In some examples, the one-shot report manager 1430 may receive, from theUE, the first feedback report multiplexed with the second feedbackreport in one or more uplink control information transmissions.

In some examples, the one-shot report manager 1430 may receive thefeedback report from the UE, where a last downlink transmission of theset of downlink transmissions that is included in the feedback report isdetermined based on a timing the downlink control information thatschedules the set of downlink transmissions, a latest downlinktransmission that meets a feedback timeline condition, or anycombinations thereof.

In some examples, the one-shot report manager 1430 may determine thelast downlink transmission as a latest downlink transmission thatscheduled in the downlink control information. In some examples, theone-shot report manager 1430 may determine the last downlinktransmission as a latest downlink transmission that scheduled in one oftwo or more different downlink control information transmissions inwhich the feedback report is requested and that indicates a same set ofuplink resources for transmitting the feedback report. In some examples,the one-shot report manager 1430 may determine the last downlinktransmission as a latest downlink transmission that is transmitted priorto transmitting the downlink control information. In some examples, theone-shot report manager 1430 may determine the last downlinktransmission as a latest downlink transmission that satisfies thefeedback timeline condition, and where the feedback timeline conditionindicates a minimum time duration at the UE between receiving a downlinktransmission and transmitting associated HARQ feedback.

In some cases, a first symbol of a set of uplink resources fortransmitting the feedback report is selected for determining the minimumtime duration, and where the first symbol of the set of uplink resourcesis determined based on one or more of uplink control informationmultiplexing of the feedback report with other uplink controlinformation, or an uplink control channel resource indicator providedwith the downlink control information.

The codebook manager 1435 may configure a codebook with a set of entriesthat are mapped to a set of different combinations of HARQ feedback fora set of feedback process identifications to be reported in the feedbackreport. In some examples, the codebook manager 1435 may identify a firstcodebook entry associated with the first feedback report, where thefirst codebook entry is mapped to a first subset of HARQ feedback andone or more parameter values associated with the first subset ofdownlink transmissions. In some examples, the codebook manager 1435 mayidentify a second codebook entry associated with the second feedbackreport, where the second codebook entry is mapped to the second subsetof HARQ feedback and one or more different parameter values than thefirst codebook entry.

The NDI manager 1440 may identify a default data indication is reportedby the UE for a first feedback process identification for which the UEhas not received scheduling information that indicates the firstfeedback process identification is to be used to indicate feedback forone of the subset of the downlink transmissions. In some cases, thedefault data indication is provided to a polar decoder to be applied asa frozen bit to assist decoding of the feedback report when schedulinginformation that indicates the first feedback process identification hasnot been transmitted to the UE. In some cases, the default dataindication is provided to the UE when scheduling information thatindicates the first feedback process identification is transmitted tothe UE.

The multiplexing component 1445 may demultiplex the HARQ feedback basedon a first codebook configured for reporting the first feedback reportand a second codebook for reporting the second feedback report. In somecases, the first feedback report is concatenated with the secondfeedback report.

The decoder 1450 may decode uplink transmissions. In some cases, apayload of each of the first feedback report and the second feedbackreport is encoded at the UE, and where the encoding is performed beforeor after the UE concatenates the first report with the second report,and where the decoder decodes the payload based on the encoding at theUE.

The feedback resource manager 1455 may receive the first feedback reportusing a first set of uplink resources. In some examples, the feedbackresource manager 1455 may receive the second feedback report using asecond set of uplink resources. In some cases, a timeline for the UE totransmit using the first set of uplink resources and the second set ofuplink resources is indicated by a feedback timing indicator that ismapped to time domain resources of the first set of uplink resources andthe second set of uplink resources.

FIG. 15 shows a diagram of a system 1500 including a device 1505 thatsupports acknowledgment feedback techniques in shared radio frequencyspectrum in accordance with aspects of the present disclosure. Thedevice 1505 may be an example of or include the components of device1205, device 1305, or a base station 105 as described herein. The device1505 may include components for bi-directional voice and datacommunications including components for transmitting and receivingcommunications, including a communications manager 1510, a networkcommunications manager 1515, a transceiver 1520, an antenna 1525, memory1530, a processor 1540, and an inter-station communications manager1545. These components may be in electronic communication via one ormore buses (e.g., bus 1550).

The communications manager 1510 may transmit a set of downlinktransmissions to a UE, the set of downlink transmissions having one ormore corresponding sets of uplink resources for transmission of HARQfeedback from the UE, determine, based on monitoring the one or moresets of uplink resources, that HARQ feedback from the UE is missing forone or more downlink transmissions of the set of downlink transmissions,and transmit, to the UE, downlink control information that indicates theUE is to provide a feedback report for a subset of downlinktransmissions, where the subset of downlink transmissions is less thanthe set of downlink transmissions.

The communications manager 1510 may also configure a UE for reportingHARQ feedback that indicates successful or unsuccessful reception of oneor more downlink transmissions at the UE, where each downlinktransmission has an associated data indicator that indicates whether thedownlink transmission includes an initial transmission of a transportblock or a retransmission of a previously transmitted transport block,and where the HARQ feedback indicates one or more of a default dataindication, a three-state indication of feedback based on anacknowledgment (ACK) and transport block indication or a negativeacknowledgment (NACK) indication, or combinations thereof, transmit aset of downlink transmissions to the UE, the set of downlinktransmissions having one or more corresponding sets of uplink resourcesfor transmission of HARQ feedback from the UE, determine, based onmonitoring the one or more sets of uplink resources, that HARQ feedbackfrom the UE is missing for one or more downlink transmissions of the setof downlink transmissions, transmit, to the UE, downlink controlinformation that indicates the UE is to provide a feedback report for atleast the one or more downlink transmissions, and receive, from the UE,the feedback report that indicates, for each of the one or more downlinktransmissions, one or more of the three-state indication of feedback,the default data indication, or any combinations thereof.

The communications manager 1510 may also transmit a first subset ofdownlink transmissions to a UE, the first subset of downlinktransmissions having one or more corresponding sets of uplink resourcesfor transmission of HARQ feedback from the UE, determine, based onmonitoring the one or more sets of uplink resources, that HARQ feedbackfrom the UE is missing for one or more downlink transmissions of thefirst subset of downlink transmissions, transmit, to the UE, downlinkcontrol information that includes a resource allocation for secondsubset of downlink transmissions and that indicates that the UE is toprovide a first feedback report for the first subset of downlinktransmissions, and where the second subset of downlink transmissionshave an associated second feedback report, and receive, from the UE, thefirst feedback report multiplexed with the second feedback report in oneor more uplink control information transmissions.

The communications manager 1510 may also transmit, to a UE, downlinkcontrol information that indicates the UE is to provide a feedbackreport for a set of downlink transmissions, receive the feedback reportfrom the UE, where a last downlink transmission of the set of downlinktransmissions that is included in the feedback report is determinedbased on a timing the downlink control information that schedules theset of downlink transmissions, a latest downlink transmission that meetsa feedback timeline condition, or any combinations thereof, anddetermine HARQ feedback based on the feedback report.

The network communications manager 1515 may manage communications withthe core network (e.g., via one or more wired backhaul links). Forexample, the network communications manager 1515 may manage the transferof data communications for client devices, such as one or more UEs 115.

The transceiver 1520 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1520 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1520 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1525.However, in some cases the device may have more than one antenna 1525,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 1530 may include RAM, ROM, or a combination thereof. Thememory 1530 may store computer-readable code 1535 including instructionsthat, when executed by a processor (e.g., the processor 1540) cause thedevice to perform various functions described herein. In some cases, thememory 1530 may contain, among other things, a BIOS which may controlbasic hardware or software operation such as the interaction withperipheral components or devices.

The processor 1540 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1540 may be configured to operate a memoryarray using a memory controller. In some cases, a memory controller maybe integrated into processor 1540. The processor 1540 may be configuredto execute computer-readable instructions stored in a memory (e.g., thememory 1530) to cause the device 1505 to perform various functions(e.g., functions or tasks supporting acknowledgment feedback techniquesin shared radio frequency spectrum).

The inter-station communications manager 1545 may manage communicationswith other base station 105, and may include a controller or schedulerfor controlling communications with UEs 115 in cooperation with otherbase stations 105. For example, the inter-station communications manager1545 may coordinate scheduling for transmissions to UEs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission. In some examples, the inter-station communications manager1545 may provide an X2 interface within an LTE/LTE-A wirelesscommunication network technology to provide communication between basestations 105.

The code 1535 may include instructions to implement aspects of thepresent disclosure, including instructions to support wirelesscommunications. The code 1535 may be stored in a non-transitorycomputer-readable medium such as system memory or other type of memory.In some cases, the code 1535 may not be directly executable by theprocessor 1540 but may cause a computer (e.g., when compiled andexecuted) to perform functions described herein.

FIG. 16 shows a flowchart illustrating a method 1600 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The operations ofmethod 1600 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 1600 may beperformed by a communications manager as described with reference toFIGS. 8 through 11. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 1605, the UE may determine HARQ feedback for a set of downlinktransmissions from a base station. The operations of 1605 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1605 may be performed by a HARQ feedbackmanager as described with reference to FIGS. 8 through 11.

At 1610, the UE may receive, from the base station, downlink controlinformation that indicates the UE is to provide a feedback report for asubset of downlink transmissions, where the subset of downlinktransmissions is less than the set of downlink transmissions. Theoperations of 1610 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1610 may beperformed by a DCI manager as described with reference to FIGS. 8through 11.

At 1615, the UE may transmit, to the base station, the feedback reportincluding the HARQ feedback for the subset of downlink transmissions.The operations of 1615 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1615may be performed by an one-shot report manager as described withreference to FIGS. 8 through 11.

FIG. 17 shows a flowchart illustrating a method 1700 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The operations ofmethod 1700 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 1700 may beperformed by a communications manager as described with reference toFIGS. 8 through 11. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 1705, the UE may determine HARQ feedback for a set of downlinktransmissions from a base station, where each of the set of downlinktransmissions has an associated data indicator that indicates whetherthe downlink transmission includes an initial transmission of downlinkdata or a retransmission of previously transmitted downlink data. Theoperations of 1705 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1705 may beperformed by a HARQ feedback manager as described with reference toFIGS. 8 through 11.

At 1710, the UE may receive, from the base station, downlink controlinformation that indicates the UE is to provide a one-shot feedbackreport for at least a subset of the downlink transmissions. Theoperations of 1710 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1710 may beperformed by a DCI manager as described with reference to FIGS. 8through 11.

At 1715, the UE may identify, for each downlink transmission of at leastthe subset of downlink transmissions, associated HARQ feedback thatincludes an ACK/NACK indication and the associated data indicator. Theoperations of 1715 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1715 may beperformed by a codebook manager as described with reference to FIGS. 8through 11.

At 1720, the UE may transmit, to the base station, the one-shot feedbackreport including the HARQ feedback for at least the subset of thedownlink transmissions. The operations of 1720 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1720 may be performed by an one-shot report manager asdescribed with reference to FIGS. 8 through 11.

FIG. 18 shows a flowchart illustrating a method 1800 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The operations ofmethod 1800 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 1800 may beperformed by a communications manager as described with reference toFIGS. 8 through 11. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 1805, the UE may receive, from a base station, a resource allocationfor a first subset of downlink transmissions. The operations of 1805 maybe performed according to the methods described herein. In someexamples, aspects of the operations of 1805 may be performed by a DCImanager as described with reference to FIGS. 8 through 11.

At 1810, the UE may determine that HARQ feedback for one or more of thefirst subset of downlink transmissions is to be provided in a firstfeedback report. The operations of 1810 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 1810 may be performed by a HARQ feedback manager asdescribed with reference to FIGS. 8 through 11.

At 1815, the UE may receive, from the base station, downlink controlinformation that indicates the UE is to provide a second feedback reportfor a second subset of downlink transmissions, where the second subsetof downlink transmissions includes one or more different downlinktransmissions than the first subset of downlink transmissions. Theoperations of 1815 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1815 may beperformed by a DCI manager as described with reference to FIGS. 8through 11.

At 1820, the UE may determine a first subset of HARQ feedback for thefirst subset of downlink transmissions and a second subset of HARQfeedback for the second subset of downlink transmissions. The operationsof 1820 may be performed according to the methods described herein. Insome examples, aspects of the operations of 1820 may be performed by aHARQ feedback manager as described with reference to FIGS. 8 through 11.

At 1825, the UE may transmit, to the base station, the first subset ofHARQ feedback multiplexed with the second subset of HARQ feedback in oneor more feedback reports. The operations of 1825 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1825 may be performed by an one-shot report manager asdescribed with reference to FIGS. 8 through 11.

FIG. 19 shows a flowchart illustrating a method 1900 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The operations ofmethod 1900 may be implemented by a UE 115 or its components asdescribed herein. For example, the operations of method 1900 may beperformed by a communications manager as described with reference toFIGS. 8 through 11. In some examples, a UE may execute a set ofinstructions to control the functional elements of the UE to perform thefunctions described below. Additionally or alternatively, a UE mayperform aspects of the functions described below using special-purposehardware.

At 1905, the UE may receive, from a base station, downlink controlinformation that indicates the UE is to provide a feedback report for aset of downlink transmissions. The operations of 1905 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1905 may be performed by a DCI manager as describedwith reference to FIGS. 8 through 11.

At 1910, the UE may determine HARQ feedback for the set of downlinktransmissions from the base station. The operations of 1910 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1910 may be performed by a HARQ feedbackmanager as described with reference to FIGS. 8 through 11.

At 1915, the UE may format the feedback report for transmission to thebase station, where a last downlink transmission of the set of downlinktransmissions to be included in the feedback report is determined basedon a timing the downlink control information that schedules the set ofdownlink transmissions, a latest downlink transmission that meets afeedback timeline condition, or any combinations thereof. The operationsof 1915 may be performed according to the methods described herein. Insome examples, aspects of the operations of 1915 may be performed by anone-shot report manager as described with reference to FIGS. 8 through11.

At 1920, the UE may transmit, to the base station, the feedback reportincluding the HARQ feedback for the set of the downlink transmissions.The operations of 1920 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 1920may be performed by an one-shot report manager as described withreference to FIGS. 8 through 11.

FIG. 20 shows a flowchart illustrating a method 2000 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The operations ofmethod 2000 may be implemented by a base station 105 or its componentsas described herein. For example, the operations of method 2000 may beperformed by a communications manager as described with reference toFIGS. 12 through 15. In some examples, a base station may execute a setof instructions to control the functional elements of the base stationto perform the functions described below. Additionally or alternatively,a base station may perform aspects of the functions described belowusing special-purpose hardware.

At 2005, the base station may transmit a set of downlink transmissionsto a UE, the set of downlink transmissions having one or morecorresponding sets of uplink resources for transmission of HARQ feedbackfrom the UE. The operations of 2005 may be performed according to themethods described herein. In some examples, aspects of the operations of2005 may be performed by a PDSCH manager as described with reference toFIGS. 12 through 15.

At 2010, the base station may determine, based on monitoring the one ormore sets of uplink resources, that HARQ feedback from the UE is missingfor one or more downlink transmissions of the set of downlinktransmissions. The operations of 2010 may be performed according to themethods described herein. In some examples, aspects of the operations of2010 may be performed by a HARQ feedback manager as described withreference to FIGS. 12 through 15.

At 2015, the base station may transmit, to the UE, downlink controlinformation that indicates the UE is to provide a feedback report for asubset of downlink transmissions, where the subset of downlinktransmissions is less than the set of downlink transmissions. Theoperations of 2015 may be performed according to the methods describedherein. In some examples, aspects of the operations of 2015 may beperformed by a DCI manager as described with reference to FIGS. 12through 15.

FIG. 21 shows a flowchart illustrating a method 2100 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The operations ofmethod 2100 may be implemented by a base station 105 or its componentsas described herein. For example, the operations of method 2100 may beperformed by a communications manager as described with reference toFIGS. 12 through 15. In some examples, a base station may execute a setof instructions to control the functional elements of the base stationto perform the functions described below. Additionally or alternatively,a base station may perform aspects of the functions described belowusing special-purpose hardware.

At 2105, the base station may configure a UE for reporting HARQ feedbackthat indicates successful or unsuccessful reception of one or moredownlink transmissions at the UE, where each downlink transmission hasan associated data indicator that indicates whether the downlinktransmission includes an initial transmission of downlink data or aretransmission of previously transmitted downlink data, and where theHARQ feedback indicates an ACK/NACK and the data indicator for each ofthe one or more downlink transmissions. The operations of 2105 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2105 may be performed by a configurationmanager as described with reference to FIGS. 12 through 15.

At 2110, the base station may transmit a set of downlink transmissionsto the UE. The operations of 2110 may be performed according to themethods described herein. In some examples, aspects of the operations of2110 may be performed by a PDSCH manager as described with reference toFIGS. 12 through 15.

At 2115, the base station may transmit, to the UE, downlink controlinformation that indicates the UE is to provide a one-shot feedbackreport for at least one or more downlink transmissions. The operationsof 2115 may be performed according to the methods described herein. Insome examples, aspects of the operations of 2115 may be performed by aDCI manager as described with reference to FIGS. 12 through 15.

At 2120, the base station may receive, from the UE, the one-shotfeedback report that indicates HARQ feedback for each of the one or moredownlink transmissions. The operations of 2120 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2120 may be performed by an one-shot report manager asdescribed with reference to FIGS. 12 through 15.

FIG. 22 shows a flowchart illustrating a method 2200 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The operations ofmethod 2200 may be implemented by a base station 105 or its componentsas described herein. For example, the operations of method 2200 may beperformed by a communications manager as described with reference toFIGS. 12 through 15. In some examples, a base station may execute a setof instructions to control the functional elements of the base stationto perform the functions described below. Additionally or alternatively,a base station may perform aspects of the functions described belowusing special-purpose hardware.

At 2205, the base station may transmit a first subset of downlinktransmissions to a UE, the first subset of downlink transmissions havingone or more corresponding sets of uplink resources for transmission ofHARQ feedback from the UE. The operations of 2205 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2205 may be performed by a PDSCH manager as describedwith reference to FIGS. 12 through 15.

At 2210, the base station may determine, based on monitoring the one ormore sets of uplink resources, that HARQ feedback from the UE is missingfor one or more downlink transmissions of the first subset of downlinktransmissions. The operations of 2210 may be performed according to themethods described herein. In some examples, aspects of the operations of2210 may be performed by a HARQ feedback manager as described withreference to FIGS. 12 through 15.

At 2215, the base station may transmit, to the UE, downlink controlinformation that includes a resource allocation for second subset ofdownlink transmissions and that indicates that the UE is to provide afirst feedback report for the first subset of downlink transmissions,and where the second subset of downlink transmissions have an associatedsecond feedback report. The operations of 2215 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2215 may be performed by a DCI manager as describedwith reference to FIGS. 12 through 15.

At 2220, the base station may receive, from the UE, the first feedbackreport multiplexed with the second feedback report in one or more uplinkcontrol information transmissions. The operations of 2220 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2220 may be performed by an one-shot reportmanager as described with reference to FIGS. 12 through 15.

FIG. 23 shows a flowchart illustrating a method 2300 that supportsacknowledgment feedback techniques in shared radio frequency spectrum inaccordance with aspects of the present disclosure. The operations ofmethod 2300 may be implemented by a base station 105 or its componentsas described herein. For example, the operations of method 2300 may beperformed by a communications manager as described with reference toFIGS. 12 through 15. In some examples, a base station may execute a setof instructions to control the functional elements of the base stationto perform the functions described below. Additionally or alternatively,a base station may perform aspects of the functions described belowusing special-purpose hardware.

At 2305, the base station may transmit, to a UE, downlink controlinformation that indicates the UE is to provide a feedback report for aset of downlink transmissions. The operations of 2305 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2305 may be performed by a DCI manager as describedwith reference to FIGS. 12 through 15.

At 2310, the base station may receive the feedback report from the UE,where a last downlink transmission of the set of downlink transmissionsthat is included in the feedback report is determined based on a timingthe downlink control information that schedules the set of downlinktransmissions, a latest downlink transmission that meets a feedbacktimeline condition, or any combinations thereof. The operations of 2310may be performed according to the methods described herein. In someexamples, aspects of the operations of 2310 may be performed by anone-shot report manager as described with reference to FIGS. 12 through15.

At 2315, the base station may determine HARQ feedback based on thefeedback report. The operations of 2315 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 2315 may be performed by a HARQ feedback manager asdescribed with reference to FIGS. 12 through 15.

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.A CDMA system may implement a radio technology such as CDMA2000,Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-2000,IS-95, and IS-856 standards. IS-2000 Releases may be commonly referredto as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) is commonly referred to asCDMA2000 1×EV-DO, High Rate Packet Data (HRPD), etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. A TDMA system mayimplement a radio technology such as Global System for MobileCommunications (GSM).

An OFDMA system may implement a radio technology such as Ultra MobileBroadband (UMB), Evolved UTRA (E-UTRA), Institute of Electrical andElectronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal MobileTelecommunications System (UMTS). LTE, LTE-A, and LTE-A Pro are releasesof UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR,and GSM are described in documents from the organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned herein as well as other systemsand radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NRsystem may be described for purposes of example, and LTE, LTE-A, LTE-APro, or NR terminology may be used in much of the description, thetechniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro,or NR applications.

A macro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEswith service subscriptions with the network provider. A small cell maybe associated with a lower-powered base station, as compared with amacro cell, and a small cell may operate in the same or different (e.g.,licensed, unlicensed, etc.) frequency bands as macro cells. Small cellsmay include pico cells, femto cells, and micro cells according tovarious examples. A pico cell, for example, may cover a small geographicarea and may allow unrestricted access by UEs with service subscriptionswith the network provider. A femto cell may also cover a smallgeographic area (e.g., a home) and may provide restricted access by UEshaving an association with the femto cell (e.g., UEs in a closedsubscriber group (CSG), UEs for users in the home, and the like). An eNBfor a macro cell may be referred to as a macro eNB. An eNB for a smallcell may be referred to as a small cell eNB, a pico eNB, a femto eNB, ora home eNB. An eNB may support one or multiple (e.g., two, three, four,and the like) cells, and may also support communications using one ormultiple component carriers.

The wireless communications systems described herein may supportsynchronous or asynchronous operation. For synchronous operation, thebase stations may have similar frame timing, and transmissions fromdifferent base stations may be approximately aligned in time. Forasynchronous operation, the base stations may have different frametiming, and transmissions from different base stations may not bealigned in time. The techniques described herein may be used for eithersynchronous or asynchronous operations.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA, or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aprocessor may also be implemented as a combination of computing devices(e.g., a combination of a DSP and a microprocessor, multiplemicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein can be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media mayinclude random-access memory (RAM), read-only memory (ROM), electricallyerasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROMor other optical disk storage, magnetic disk storage or other magneticstorage devices, or any other non-transitory medium that can be used tocarry or store desired program code means in the form of instructions ordata structures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, include CD, laser disc, optical disc,digital versatile disc (DVD), floppy disk and Blu-ray disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above are also includedwithin the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items(e.g., a list of items prefaced by a phrase such as “at least one of” or“one or more of”) indicates an inclusive list such that, for example, alist of at least one of A, B, or C means A or B or C or AB or AC or BCor ABC (i.e., A and B and C). Also, as used herein, the phrase “basedon” shall not be construed as a reference to a closed set of conditions.For example, an exemplary step that is described as “based on conditionA” may be based on both a condition A and a condition B withoutdeparting from the scope of the present disclosure. In other words, asused herein, the phrase “based on” shall be construed in the same manneras the phrase “based at least in part on.”

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or othersubsequent reference label.

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communications at a userequipment (UE), comprising: determining hybrid automatic repeat request(HARQ) feedback for a set of HARQ processes associated with downlinktransmissions from a base station, wherein each HARQ process of the setof HARQ processes has an associated data indicator that indicateswhether the associated downlink transmission includes an initialtransmission of downlink data or a retransmission of previouslytransmitted downlink data; receiving, from the base station, downlinkcontrol information that indicates the UE is to provide a one-shotfeedback report for at least a subset of the HARQ processes;identifying, for each HARQ process of at least the subset of HARQprocesses, associated HARQ feedback that includes anacknowledgment/negative-acknowledgment indication of the downlinktransmission associated with the HARQ process and the associated dataindicator that indicates whether the associated downlink transmissionincludes an initial transmission of downlink data or a retransmission ofpreviously transmitted downlink data, wherein a default data indicatoris identified as the associated data indicator for one or more HARQprocesses in an absence of scheduling information for the associatedHARQ process; and transmitting, to the base station, the one-shotfeedback report including the HARQ feedback and the associated dataindicator for each HARQ process of at least the subset of the HARQprocesses.
 2. The method of claim 1, wherein the transmitting comprises:transmitting only the one-shot feedback report with an uplinktransmission to the base station.
 3. The method of claim 1, wherein theone-shot feedback report includes one or more of acknowledgment (ACK)indications, negative acknowledgment (NACK) indications, the dataindicator, or combinations thereof, that are each associated with acorresponding HARQ process of the subset of HARQ processes.
 4. Themethod of claim 1, wherein the data indicator is a new data indicator(NDI) that is included in the one-shot feedback report based on aconfiguration to include NDI information with the HARQ feedback.
 5. Themethod of claim 1, wherein the set of HARQ processes includes aplurality of HARQ processes that each have a different HARQ processidentification.
 6. The method of claim 1, wherein the one-shot feedbackreport provides HARQ feedback and the associated data indicator for eachof a plurality of HARQ process IDs, and wherein the HARQ feedback isassociated with one or more of a plurality of transport blocks, aplurality of component carriers, a plurality of code block groups, orany combinations thereof.
 7. The method of claim 1, wherein theidentifying the associated HARQ feedback comprises: identifying acodebook associated with the HARQ feedback for at least the subset ofHARQ processes to be reported in the one-shot feedback report.
 8. Themethod of claim 1, wherein a latest HARQ process of the set of HARQprocesses to be included in the one-shot feedback report is determinedbased at least in part on a timing of downlink control information thatschedules the downlink transmissions, a latest downlink transmissionthat meets a feedback timeline condition, or any combinations thereof.9. A method for wireless communications at a base station, comprising:configuring a user equipment (UE) with a set of hybrid automatic repeatrequest (HARQ) processes to provide feedback that indicates successfulor unsuccessful reception of one or more downlink transmissions at theUE, wherein each HARQ process has an associated data indicator thatindicates whether the associated downlink transmission includes aninitial transmission of downlink data or a retransmission of previouslytransmitted downlink data, and wherein the HARQ feedback indicates, foreach HARQ process, an acknowledgment/negative-acknowledgment of thedownlink transmission and the associated data indicator of the downlinktransmission that indicates whether the associated downlink transmissionincludes an initial transmission of downlink data or a retransmission ofpreviously transmitted downlink data; transmitting a set of downlinktransmissions to the UE; transmitting, to the UE, downlink controlinformation that indicates the UE is to provide a one-shot feedbackreport for at least at least a subset of the set of HARQ processes; andreceiving, from the UE, the one-shot feedback report that indicates HARQfeedback and the associated data indicator for each of at least thesubset of the set of HARQ processes, wherein a default data indicator isincluded with the HARQ feedback for one or more of the HARQ processes inan absence of scheduling information for the associated HARQ process.10. The method of claim 9, wherein the one-shot feedback report istransmitted with an uplink transmission of the UE, and wherein only theone-shot feedback report is provided with the uplink transmissionirrespective of whether a HARQ reporting timeline of one or more othertypes of HARQ feedback corresponds to a timing of the uplinktransmission.
 11. The method of claim 9, wherein the one-shot feedbackreport includes one or more of acknowledgment (ACK) indications,negative acknowledgment (NACK) indications, the data indicator, orcombinations thereof, that are each associated with a corresponding HARQprocess of the subset of HARQ processes.
 12. The method of claim 11,wherein the data indicator is a new data indicator (NDI).
 13. The methodof claim 11, wherein the set of HARQ processes includes a plurality ofHARQ processes that each have a different HARQ process ID.
 14. Themethod of claim 9, wherein the one-shot feedback report provides HARQfeedback and the associated data indicator for each of a plurality ofHARQ process IDs, and wherein the HARQ feedback is associated with oneor more of a plurality of transport blocks, a plurality of componentcarriers, a plurality of code block groups, or any combinations thereof.15. The method of claim 9, wherein the default data indicator isreported by the UE for a first feedback process identification for whichthe UE has not received scheduling information that indicates the firstfeedback process identification is to be used to indicate feedback forone of the downlink transmissions.
 16. The method of claim 15, whereinthe default data indicator is applied at a polar decoder as a frozen bitto assist decoding of the feedback report when scheduling informationthat indicates the first feedback process identification has not beentransmitted to the UE.
 17. The method of claim 9, wherein a latest HARQprocess of the set of HARQ processes to be included in the one-shotfeedback report is determined based at least in part on a timing ofdownlink control information that schedules the set of downlinktransmissions, a latest downlink transmission that meets a feedbacktimeline condition, or any combinations thereof.
 18. An apparatus forwireless communications at a user equipment (UE), comprising: aprocessor, memory coupled with the processor; and instructions stored inthe memory and executable by the processor to cause the apparatus to:determine hybrid automatic repeat request (HARQ) feedback for a set ofHARQ processes associated with downlink transmissions from a basestation, wherein each HARQ process of the set of HARQ processes has anassociated data indicator that indicates whether the associated downlinktransmission includes an initial transmission of downlink data or aretransmission of previously transmitted downlink data; receive, fromthe base station, downlink control information that indicates the UE isto provide a one-shot feedback report for at least a subset of the HARQprocesses; identify, for each HARQ process of at least the subset ofHARQ processes, associated HARQ feedback that includes anacknowledgment/negative-acknowledgment indication of the downlinktransmission associated with the HARQ process and the associated dataindicator that indicates whether the associated downlink transmissionincludes an initial transmission of downlink data or a retransmission ofpreviously transmitted downlink data, wherein a default data indicatoris identified as the associated data indicator for one or more HARQprocesses in an absence of scheduling information for the associatedHARQ process; and transmit, to the base station, the one-shot feedbackreport including the HARQ feedback and the associated data indicator foreach HARQ process of at least the subset of the HARQ processes.
 19. Theapparatus of claim 18, wherein the instructions are further executableby the processor to cause the apparatus to: transmit only the one-shotfeedback report with an uplink transmission to the base stationirrespective of whether a HARQ reporting timeline of one or more othertypes of HARQ feedback corresponds to a timing of the uplinktransmission.
 20. The apparatus of claim 18, wherein the one-shotfeedback report includes one or more of acknowledgment (ACK)indications, negative acknowledgment (NACK) indications, the dataindicator, or combinations thereof, that are each associated with acorresponding HARQ process of the subset of HARQ processes.
 21. Theapparatus of claim 20, wherein the data indicator is a new dataindicator (NDI) that is included in the one-shot feedback report basedon a configuration to include NDI information with the HARQ feedback.22. The apparatus of claim 20, wherein the set of HARQ processesincludes a plurality of HARQ processes that each have a different HARQprocess ID.
 23. The apparatus of claim 18, wherein the one-shot feedbackreport provides HARQ feedback and the associated data indicator for eachof a plurality of HARQ process IDs, and wherein the HARQ feedback isassociated with one or more of a plurality of transport blocks, aplurality of component carriers, a plurality of code block groups, orany combinations thereof.
 24. The apparatus of claim 18, wherein theinstructions are further executable by the processor to cause theapparatus to: identify a codebook associated with the HARQ feedback forat least the subset of HARQ processes to be reported in the one-shotfeedback report.
 25. An apparatus for wireless communications at a basestation, comprising: a processor, memory coupled with the processor; andinstructions stored in the memory and executable by the processor tocause the apparatus to: configure a user equipment (UE) with a set ofhybrid automatic repeat request (HARQ) processes to provide feedbackthat indicates successful or unsuccessful reception of one or moredownlink transmissions at the UE, wherein each HARQ process has anassociated data indicator that indicates whether the associated downlinktransmission includes an initial transmission of downlink data or aretransmission of previously transmitted downlink data, and wherein theHARQ feedback indicates, for each HARQ process, anacknowledgment/negative-acknowledgment of the downlink transmission andthe associated data indicator of the downlink transmission thatindicates whether the associated downlink transmission includes aninitial transmission of downlink data or a retransmission of previouslytransmitted downlink data; transmit a set of downlink transmissions tothe UE; transmit, to the UE, downlink control information that indicatesthe UE is to provide a one-shot feedback report for at least at least asubset of the set of HARQ processes; and receive, from the UE, theone-shot feedback report that indicates HARQ feedback and the associateddata indicator for each of at least the subset of the set of HARQprocesses, wherein a default data indicator is included with the HARQfeedback for one or more of the HARQ processes in an absence ofscheduling information for the associated HARQ process.
 26. Theapparatus of claim 25, wherein the one-shot feedback report istransmitted with an uplink transmission of the UE, and wherein only theone-shot feedback report is provided with the uplink transmissionirrespective of whether a HARQ reporting timeline of one or more othertypes of HARQ feedback corresponds to a timing of the uplinktransmission.
 27. The apparatus of claim 25, wherein the one-shotfeedback report includes one or more of acknowledgment (ACK)indications, negative acknowledgment (NACK) indications, the dataindicator, or combinations thereof, that are each associated with acorresponding HARQ process of the subset of HARQ processes.
 28. Theapparatus of claim 27, wherein the data indicator is a new dataindicator (NDI).
 29. The apparatus of claim 27, wherein the set of HARQprocesses includes a plurality of HARQ processes that each have adifferent HARQ process ID.
 30. The apparatus of claim 25, wherein theone-shot feedback report provides HARQ feedback and the associated dataindicator for each of a plurality of HARQ process IDs, and wherein theHARQ feedback is associated with one or more of a plurality of transportblocks, a plurality of component carriers, a plurality of code blockgroups, or any combinations thereof.